Ellipsis alternation in Norwegian: language production shapes language comprehension

Transcription

1 Ellipsis alternation in Norwegian: language production shapes language comprehension Joanna Nykiel Abstract Two eye movement studies explored online comprehension of sluicing remnants with and without prepositions in Norwegian, as an instance of what I dub ellipsis alternation. The context in which remnants were used was manipulated in terms of the informativity of their correlates and the absence/presence of semantic dependencies between prepositions and verbs. Two kinds of processing difficulty were observed. First, go-past time on the remnant region was longer for remnants with prepositions than for remnants without prepositions, if prepositions were semantically dependent on verbs. Second, more regressions were launched from the remnant region for remnants with prepositions than for remnants without prepositions, if prepositions were semantically dependent on verbs. Two acceptability judgment studies following these experiments supported the findings: remnants with prepositions that were more often regressed from were also degraded in the same context. Data from both sources closely track the distribution of remnants found in language production data. I conclude that these results are consistent with experience-based accounts of language processing, which assume that the statistics of linguistic input shape language processing. I discuss how these findings contribute to our understanding of why biases toward one type of remnant over the other differ across languages. 1 Introduction Consider the two elliptical questions following the sentence in (1). (1) A: Pat is staying in Paris with someone. B 1 : Who? B 2 : With who? 1

2 The question in B 1 is omitting the preposition with, which is present in the antecedent (the A-sentence), and the question in B 2 is not, while both are conveying the same meaning. Let us term this alternation ellipsis alternation, following Nykiel (2014, To appear). These examples illustrate ellipsis alternation in sluicing, an elliptical construction with a wh-phrase acting as the remnant and having the function of an interrogative clause. 1 Discussion of ellipsis alternation has largely been constrained to the ellipsis literature. A question of primary interest has been whether ellipsis alternation is generally available or unique to select few languages. Merchant (2001) argues that the availability of ellipsis alternation correlates with the possibility to strand prepositions in nonelliptical interrogative clauses, as in (2). Since this possibility exists in a subset of the Germanic languages, they are the ones allowing the alternation. This apparent correlation leads Merchant (2001) to conclude that the availability of ellipsis alternation is subject to a categorical grammatical constraint and can be used as a diagnostic of unpronounced structure for sluicing remnants. The alternatives in example (1) would be derived from two corresponding interrogative clause sources, shown in (3) (the unpronounced material is indicated by strikethrough). (2) Who is Pat staying in Paris with? (3) A: Pat is staying in Paris with someone. B 1 : Who is Pat staying in Paris with? B 2 : With who is Pat staying in Paris? Subsequent research has shown that ellipsis alternation extends far beyond the languages with preposition stranding, and even beyond environments allowing preposition stranding in English. It is found in Romance and Slavic languages, as well as Bahasa Indonesia and Amis, although these languages differ in terms of preferences for remnants without prepositions over remnants with prepositions (Merchant 2001, Almeida and Yoshida 2007, Fortin 2007, Sato 2011, 1 Another elliptical construction that allows this alternation is Bare Argument Ellipsis, where the remnant phrase has the function of a declarative clause, as in (i)-(ii). As is clear from these examples, the remnant can act as a response to an antecedent question, as in (i), but needn t do so. (i) (ii) A: Which building is Pat in? B 1 : Hayden Hall. B 1 : In Hayden Hall. Kim s sister is proud of her for her modeling career, but not telling the truth/but not for telling the truth. 2

3 Szczegielniak 2008, Nykiel 2013, Kluck 2011, Caha 2011, Rodrigues et al. 2009, Stjepanović 2008, Vicente 2008, Wei 2011). This research raises a theoretically important question: what constraints in fact account for the availability of ellipsis alternation? It is a distinct possibility that what Merchant (2001) takes to be a categorical grammatical constraint is instead a conventionalized preference for remnants without prepositions over remnants with prepositions (or the reverse) that follows from principles of language processing, along the lines of Hawkins (2004, 2014). A recent strand of research addresses this question by exploring ellipsis alternation from the perspective of syntactic variation (Nykiel 2013, 2014, To appear). The main findings are that constraints on ellipsis alternation can be captured by three performance preferences that have been independently observed in research on anaphora, constituent ordering, and structural persistence, and which have been motivated by the efficiency of language processing and production. Evidence for these preferences comes from corpus and acceptability judgment studies of English and Polish. However, there are no studies of the online comprehension of instances of ellipsis alternation. In this paper, I explore whether one type of remnant is easier to process than the other in contexts where they differ in terms of frequency and acceptability. By doing this, I ask whether online comprehension of remnants reveals independent processing difficulty or whether speakers are simply following patterns of preference found in their input. The rest of this paper is structured as follows. The next section overviews the nature of the constraints on ellipsis alternation. Section 3 discusses the relationship among two data sources (corpus evidence and online processing) in terms of what they reveal about the production and comprehension of linguistic structure. In section 4, I present the results of two online comprehension studies of ellipsis alternation in Norwegian followed by two acceptability judgment studies of the same data. Section 5 explores the implications of the results for our understanding of the nature of ellipsis alternation and the way it differs across languages. Section 6 concludes. 2 Constraints on ellipsis alternation The literature addressing the question of what constraints ellipsis alternation is subject to is still sparse. What emerges from this literature is that remnant choice is affected by the features of the linguistic environments in which remnants occur. Specifically, these features relate to remnants correlates and to the relationship between prepositions and their lexical heads. I first address the features relating to correlates. 3

4 A remnant s correlate is the PP embedded in the antecedent clause which provides a referent for the remnant. The PP with someone in example (1) is the correlate for the remnants in B 1 and B 2. Two features of the correlate have been shown to significantly affect remnant choice: the syntactic form of the correlate and its informativity. The syntactic form of the correlate in (1) is a PP, but imagine a modified version of (1), shown in (4). (4) A: Pat is staying in Paris with someone. B: Yes, his partner. A 1 : Really, who? A 2 : Really, with who? Now the correlate for the remnants in the A 1 and A 2 questions appears as the NP his partner. In English corpus data, A 1 is more likely than A 2 to follow an NP correlate like that in (4), but B 2 is more likely than B 1 to follow a PP correlate like that in (1) (Nykiel 2014, To appear). This pattern of results may be attributed to structural persistence effects, regularly observed both in monologue and dialog, such that speakers reuse syntactic structure to which they have been previously exposed even though other grammatical options are available to them. Such reuse is observed not just at the level of syntax, but also at other levels of linguistic description (Meyer and Schvaneveldt 1971, Levelt and Kelter 1982, Kempley and Morton 1982, Tanenhaus et al. 1980, Weiner and Labov 1983, Bock 1986, Hartsuiker and Westenberg 2000, Branigan et al. 2000, and Szmrecsanyi 2005). In sluicing, speakers reuse the syntactic structure witnessed in the immediately surrounding discourse, that is, in the correlate. Correlates that contain no prepositions support the appearance of sluicing remnants without prepositions. 2 A correlate s informativity includes both its semantic and syntactic features. Nykiel (2014, To appear) formalizes this notion as the ratio of features actually encoded by a phrase to features that could possibly be encoded. In this system, all phrases serving as prepositional objects are associated with informativity scores. Simply put, informativity scores are calculated based on a set of general semantic and syntactic features which reflect the specificity with which a phrase 2 Structural persistence effects are in fact not only induced by correlates that contain no prepositions, such as example (4), but also by preposition stranding in languages that allow it. In English Bare Argument Ellipsis, for example, the remnant in (i) is more likely to appear without the preposition than with it, if the correlate s constituents are discontinuous due to preposition stranding. (i) A: Who is Pat staying in Paris with? B 1 : His partner. B 2 : With his partner. 4

5 describes its referent. For instance, NPs always receive higher informativity scores than indefinite pronouns, because they are specified for more semantic features than indefinite pronouns are. Features that NPs are specified for include animacy (animate or inanimate referents), concreteness (physical or abstract referents), and natural gender (feminine, masculine, or neuter), while features that indefinite pronouns are specified for are limited to humanness (human or nonhuman referents). Compare the correlate in example in (1), hosting an indefinite pronoun, with the one in (5), hosting an NP. (5) A: Pat is staying in Paris with a girlfriend. B 1 : Which girlfriend? B 2 : With which girlfriend? More informative correlates like those in (5) have a greater tendency, which is statistically significant, to co-occur with remnants without prepositions (B 1 ) than correlates like those in (1) do. This tendency may be explained by the inherent accessibility of informative phrases, which is mediated not only by how they are specified for semantic features (Prat-Sala and Branigan 2000), but also for how many. More accessible phrases are more readily available for future reference, and so require fewer retrieval cues at the point at which they are reaccessed (Ariel 1990, Hofmeister 2011). Assuming that remnants without prepositions provide fewer retrieval cues, they serve to retrieve more accessible correlates. As for the relationship between prepositions and their lexical heads, there may be a semantic dependency between a preposition and its lexical head, which is seen in both the correlate and the remnant. To see this, consider (6). (6) A: A nurse came in and checked in on someone. B 1 : Who? B 2 : On who? This semantic dependency is best understood in processing terms (following Hawkins 2000, 2004), such that the preposition on cannot be parsed without reference to the verb check in, which acts as the lexical head, and the verb cannot be parsed without reference to the preposition. 3 Since the remnant corresponds to the correlate, the semantic dependency holds true of both. Note that there is no such dependency between the preposition in and its lexical head (stay) in example (1): one can parse the verb without access to the preposition and the preposition without access to the verb. 3 The semantic relationship needn t be mutual. For some prepositions and their lexical heads, the preposition cannot be parsed without access to the lexical head, but not vice versa. 5

6 A robust effect of semantic dependencies is evident in English corpus data (Nykiel 2014). The probability of remnants appearing without prepositions is much higher if these prepositions are semantically dependent on the lexical heads than if they are not. Thus, B 1 is more likely than B 2 in example (6) than in example (1). This effect mirrors the preference for semantically dependent lexical items to be placed adjacent to each other in nonelliptical clauses. For instance, the order of two post-verbal PPs is sensitive to whether a semantic dependency holds between the verb and one of the prepositions (Hawkins 2000). Example (7) illustrates a semantic dependency between the verb look and the preposition at, leading to a preference for the order where this preposition directly follows the verb. (8) illustrates the alternative, dispreferred, word order, with the dependent items separated by the second PP and the recognition of the dependency by the parser delayed. (7) Let s go look at the moon through the telescope eyepiece. (8) Let s go look through the telescope eyepiece at the moon. The similarity of constituent ordering and the behavior of ellipsis remnants indicates that the human parser prefers simultaneous access to lexical items that are semantically dependent, and that retaining one but not the other in an ellipsis remnant (note that the verbal head can never be present in a sluicing remnant) disrupts the recognition of the dependency in a similar way that separating the items does in constituent ordering. Given these three preferences influencing the realization of remnants, it is possible to predict how languages might differ in terms of the overall preference for a particular kind of remnant. The preference for retrieving accessible antecedents with fewer retrieval cues is expected to be a fully general preference, while the strength of the effects of semantic dependencies and structural persistence varies. Nykiel (2013, 2014) demonstrates a clear preference for remnants without prepositions in English and the reverse preference in Polish. What differs between the two languages is the strength of semantic dependencies and the frequency of correlates appearing without prepositions. These factors are interrelated in the sense that stronger semantic dependencies increase the frequency of remnants without prepositions, which in turn can become correlates for further remnants, and, if so, appear as correlates containing no prepositions. One clear case of strong semantic dependencies in English are prepositional verbs. We saw one example in (6): the verb check in and the preposition on form a noncompositional unit. This means that the semantic dependency is always a two-way dependency for prepositional verbs, because the verb depends on the preposition and the preposition depends on the verb. The examples 6

7 in (9) and (10) make it clear that remnants with prepositions are strongly dispreferred if prepositional verbs are used in the antecedent clauses. (9) come across Pat came across something down in the basement, but he didn t say what/?across what. (10) fall for Pat fell for something silly again, but I m not sure what/?for what. Because prepositional verbs are available in English, but not in Polish, so are two-way dependencies the strongest type of semantic dependencies. There is evidence that English used to prefer remnants with prepositions over remnants without prepositions, and has only developed the preference for the latter over time and in parallel with the development of prepositional verbs (Nykiel To appear). This suggests that the preference for remnants with prepositions may be the default option, with remnants without prepositions tending to appear with informative correlates, but that this preference can be compromised by the presence of strong semantic dependencies between the relevant lexical categories. This analysis of ellipsis alternation is fully consistent with the Performance-Grammar Correspondence Hypothesis (PGCH), as defined by Hawkins (2004: 3) and given in (11). (11) Performance-Grammar Correspondence Hypothesis Grammars have conventionalized syntactic structures in proportion to their degree of preference in performance, as evidenced by patterns of selection in corpora and by ease of processing in psycholinguistic experiments. The central idea behind the PGCH is that grammatical conventions and patterns of linguistic variation are shaped by performance preferences. The data discussed above support this idea: ellipsis alternation reflects the extent to which the strength of three performance preferences found in a given language leads to one kind of remnant being favored over the other in certain contexts or even overall in the language. Thus far, however, the supporting evidence for these preferences largely comes from language production data. Hence, it reflects the speaker s perspective as opposed to the comprehender s or hearer s. It remains an open question whether any difficulty is involved in the processing of different types of remnants from the comprehender s perspective. The next section overviews differences among data collected from sources that contrast in terms of whether they reflect the speaker s or comprehender s perspective. 7

8 3 Language production data and language comprehension data Data collected through studies of language production are not always consistent with data collected through studies of language comprehension. One example of how studies of language production and studies of language comprehension diverge in their findings is English heavy NP shift. Example (12) illustrates the shifted order of the two postverbal phrases, with the longer direct object NP appearing in sentence-final position. In (13), the longer NP is adjacent to the verb, preceding the shorter PP in the canonical order. (12) It s to sell to people a sound that will be popular among the masses. (13) It s to sell a sound that will be popular among the masses to people. One influential account of constituent ordering makes the prediction that a postverbal constituent will be displaced, as in (12), if its weight (as measured in number of words) is greater than the weight of another constituent that follows it in the canonical order (Hawkins 2004). Hawkins (2004) argues that word order choice follows the Early Immediate Constituents (EIC) and Minimize Domains (MiD) principles, so that a postverbal constituent is extraposed when it is lengthier than another postverbal constituent, avoiding a considerable delay in parsing all the constituents of the VP. Consistent with the EIC and MiD, what determines word order choice in corpus data is the relative length of the postverbal phrases: the longer the direct object NP is than the second phrase, the greater the preference for the shifted order shown in (12) (Wasow and Arnold 2003). We would expect that the shifted order comes with some processing advantage for cases of a large length difference between postverbal phrases. However, Staub et al. (2006) demonstrate that the shifted order causes processing difficulty compared to the canonical order. This study did not explicitly control for relative length of postverbal phrases, although a look at the experimental items reveals that the direct object NP was consistently longer (by four or more words) than the other phrase. Given this context, the shifted order should not have seemed unusual to the comprehender or induced processing difficulty. On the other hand, Staub et al. (2006) also find that the processing difficulty that heavy NP shift induces compared to the canonical order depends on the verb s transitivity bias. The difficulty appears on the material intervening between the verb and its direct object, as in (14) from Staub et al. (2006: 394), if the verb is obligatorily transitive. It is manifested by a disruption to the progression of eye movements over the course of the sentence so that the 8

9 eyes return to a previous part of the sentence instead of moving forward. 4 (14) The teacher corrected immediately the unusual answer the student had given. For optionally transitive verbs, the disruption appears on the verb s direct object and takes the form of inflated reading times, but not regressive eye movements. Staub et al. (2006) suggest that these results may be interpreted in terms of the overall frequency of the shifted word order in English. Because this word order is infrequent (Wasow (1997), it causes processing difficulty. At the same time, the transitivity bias of a verb influences the type and location of the difficulty. Obligatorily transitive verbs incur the difficulty as soon as material other than the direct object is encountered following them. The parser expects the direct object and when this expectation is violated, regressive eye movements are programmed. Optionally transitive verbs do not come with such an expectation (they are also found with heavy NP shifted word orders more often than obligatorily transitive verbs, according to Wasow 1997), and so the material intervening between the verb and the direct object does not cause processing difficulty, but when the direct object is encountered it needs to be accommodated into the argument structure being built. Thus, Staub et al. (2006) conclude that processing difficulty may occur as the result of violated expectations about the upcoming structure. Such expectation-based biases are implemented in surprisal theory offered by Hale (2001) and Levy (2008). Hale s (2001) and Levy s (2008) proposals assume that speakers have probabilistic information about linguistic input, which guides them in interpreting this input and in predicting upcoming material. Words in given constructions have surprisal values which can be used to precisely estimate what processing difficulty may appear if expectations about these constructions are violated. Parallels between language production and comprehension behavior are also central to MacDonald s (1999, 2013) Production Distribution Comprehension (PDC) account. On this account, patterns appearing in production data are relevant to the way speakers comprehend linguistic material. In particular, some comprehension biases which have been identified in language comprehension literature are linked to the distribution of linguistic forms found in production data. For instance, there is a clear bias for attaching clause-final adverbials low rather than high. (15), from MacDonald (2013: 9), illustrates an adverbial that could be attached high (the matrix-clause VP) or low (the 4 This difficulty was manifested as both increased regressions and inflated first pass time (that is, the time spent on a word/region before moving off of it for the first time) if the postverbal material was a PP instead of an adverb. Staub et al. (2006) speculate that is was due to the differing length of PPs compared to adverbs. 9

10 embedded VP). (15) John said that his cousins left yesterday. Although in principle ambiguous, the adverbial s attachment is overwhelmingly interpreted as low, which, MacDonald (1999, 2013) argues, is due to speakers previous experience of similar sentences. Given that a short adverbial like yesterday can appear immediately after the matrix verb and before the longer embedded clause, disambiguating its role in the meaning of the clause, the unusual choice of clause-final position is purposeful: it indicates the low attachment. In sum, comparison of production and comprehension data yields conflicting results. On the one hand, it shows that speakers bring their experience as producers of linguistic material to the task of comprehending someone else s output. On the other, it indicates that we should not automatically assume that choices that have some advantage from the speaker s perspective have a corresponding advantage from the comprehender s perspective. 4 Ellipsis alternation in Norwegian Norwegian and English behave similarly in terms of the bias toward remnants without prepositions. In support of this claim, I offer data extracted from the Norwegian Speech Corpus the Oslo part (NoTa-Oslo). 5 I extracted all instances of ellipsis alternation, both in sluicing and Bare Argument Ellipsis, by first extracting all wh-phrases. I then manually checked the contexts in which these phrases were embedded to find relevant examples of sluicing (with whphrases acting as remnants) or Bare Argument Ellipsis (with wh-phrases acting as correlates for remnants). These procedures yielded a sample of twenty-five items. The majority of these items host remnants without prepositions (22; 88%), leaving little doubt that this is the preferred type of remnant in Norwegian. The sample is too small to warrant a reliable statistical analysis, so let us instead take a closer look at the three remnants which do host prepositions. All are given in (16) (18) below. The remnants are indicated in bold. (16) A: Den går bak Vålerenga kirke. B: På hvilken side av den A: It goes behind Vålerenga church B: on which side of the store big veien? road the A: A: På høyresida. on right side 5 This 900,000-word corpus contains interviews with Norwegian speakers from Oslo and the Oslo area. It is available online at: 10

11 A: It goes behind the Vålerenga church. B: On which side of the big road? A: On the right side. (17) A: Men er det en film? A: but is that a film B: Ja, ja. A: Med hvem da? B: yes, yes A: with who then Med han selv? with himself A: But is this a film? B: Yes, yes. A: With who then? With himself? (18) A: Du dro dit med venner? B: Mm... A: Med hvem? A: you went there with friends B: um A: with who A: You went there with friends? B: Um... A: With who? Recall from section 2 that the likelihood that remnants with prepositions will appear increases if the constituents of their correlates are adjacent, as is the case in all of the examples above. Another factor that promotes use of such remnants is low informativity of the prepositional object embedded in the correlate. In (17), this object is indeed low in informativity due to being an indefinite pronoun, while in (16) and (18) it is a more informative phrase an NP. Finally, none of these remnants and their corresponding correlates show any semantic dependency on the VPs found in the antecedents, and hence they may be parsed independently of the VPs (Note that all of the correlate PPs are adjuncts in the antecedent clauses). For instance, the VP in (18) may be replaced with a proform, yielding You did that with friends?, without any loss of interpretability for the final PP. Considered from the point of view of language production, Norwegian speakers remnant choices are consistent with choices made by English speakers. In particular, the corpus data provide strong support in favor of a consistent preference for remnants without prepositions in the language, as well as the effect of semantic dependencies (given that none of the remnants with prepositions appear in items showing a semantic dependency between these remnants and the lexical heads), much like that observed in English. The effect of semantic dependencies in Norwegian is not unexpected, because it has prepositional verbs (e.g., gå inn for support, se opp til look up to, or ta etter take after ) providing the strongest degree of dependency. Before turning to an experimental investigation of how the biases identified in production behavior play out in an online comprehension task, I briefly overview existing literature on whether any processing difficulty is associated with different types of anaphors, if the antecedent is held constant. Sluicing shares with other anaphoric constructions the property that it requires that the parser establish a link between an anaphor and its antecedent. 11

12 The specific question that ellipsis alternation raises in this context is whether choice of different types of anaphors influences the difficulty with which this link is established. Some related evidence comes from studies of nominal anaphora, where the choice is available between a pronoun and a definite NP, which is typically a repetition of the antecedent, as in (19). In this example, the same antecedent (My mom) may be referred to by means of a pronoun (She) or a repetitive NP (My mom), although the latter is disfavored. (19) My mom teases me a lot. She/My mom makes fun of things that I say. It is commonly reported that if the antecedent is the most salient referent in the current discourse, as is the case in (19), an NP is more difficult to process than a pronoun (Hudson et al. 1986, Gordon et al. 1993). 6 Processing difficulty appears on the anaphor itself (Duffy and Rayner 1990). This pattern of results is easily explained, if we assume that an NP anaphor carries more semantic content than is necessary to retrieve a salient antecedent (see Ariel 1990). It is possible that some processing difficulty might appear on sluicing remnants with prepositions in contexts in which they are disfavored in natural discourse (e.g. when the correlate is already accessible due to its informativity). 4.1 Experiment 1 The experiment described in this section addresses three questions raised by research on ellipsis alternation. The first question is whether the preference for remnants without prepositions translates into processing difficulty on the preposition if it is present in the remnant. The second question asks whether any processing difficulty is associated with pairing remnants with prepositions and informative correlates, and if so, how this difficulty is manifested. The last question asks whether remnants with prepositions induce a processing difficulty when there is a semantic dependency between the prepositions and their lexical heads. To put it differently, the experiment asks to what extent biases toward a particular kind of remnant in language production shape online comprehension. I hypothesized that the type of remnant that is less frequent in language production may induce processing difficulty at the point that it is encountered, because it violates an expectation for the more frequent alternative. How this difficulty is manifested, if in fact observed, is the focus of Experiment 1. The experiment examined eye movement patterns on each word within the regions 6 But see also evidence that an NP may have a processing advantage over a pronoun (Chang 1980), and that there may be no processing difference between the two (Marslen-Wilson and Tyler 1980, Clifton and Ferreira 1987). 12

13 of interest in sluicing, as explained below Participants Eighty students at the University of Stavanger participated in the experiment in exchange for an entry in a lottery organized by the National Reading Center. All of the participants were native and monolingual speakers of Norwegian, and had normal or corrected-to-normal vision Materials The experimental materials consisted of forty-eight sets of four sentences, similar to the sluicing examples in (20) and (21). In each set, one pair of sentences differed from the other in terms of the informativity of the phrase embedded in the correlate: this phrase was either an indefinite pronoun (21) or an NP (20). The only difference between the two sentences in each pair was whether or not the remnant appeared with a preposition (the different remnant versions are set off by slashes in the examples below). (20) Stig har fortalt om en studentenfest, men jeg vet ikke om Stig has told about a student party but I know not about hvilken/hvilken og jeg er which/which and I am indifferent Stig has told us about some student party but I don t know about which/which and I don t care. (21) Stig har fortalt om noe, men jeg vet ikke om Stig has told about something but I know not about hva/hva og jeg er what/what and I am indifferent Stig has told us about something but I don t know about what/what and I don t care. One half of these sets (Set 1) used verbs and prepositions that were semantically independent of each other, while the other half (Set 2) used prepositions that depended on verbs for their interpretation. Examples (20) and (21) illustrate semantic dependency of the preposition om on the verb. Example (22) shows a preposition that is semantically independent of the verb. 13

14 (22) Terje har syklet over en bro, men jeg vet ikke over Terje has biked over a bridge but I know not over hvilken/hvilken og jeg er which/which and I am indifferent Terje has biked over a bridge but I don t know which and I don t care. As a means to ensure that prepositions were semantically dependent on the verbs used in half of the items, I conducted a norming study. A separate group of fifteen participants provided completions of sentence fragments that consisted of the subjects and verbs from all the items (including experimental items I used in Experiments 3 and 4, as discussed in sections 4.3 and 4.4). The expectation was that the next words should be the semantically dependent prepositions for the semantically dependent items, because such prepositions usually co-occur with verbs as part of their subcategorization frame. For the semantically dependent sentence fragments, no less than 85% of the completions included the expected prepositions. For the semantically independent items, only 7% of the completions included the prepositions I actually used, with the remaining completions ranging from adverbs/adjectives to adverbial clauses to PPs with different prepositions. The results of this study confirm the expected dependency relations between the prepositions and verbs in the experimental items. This design made it possible to test the prediction that the difficulty of processing a remnant may depend on any or all of these factors: (1) presence or absence of prepositions, (2) informativity of the correlate, or (3) semantic dependency between verbs and prepositions or lack thereof. The experimental items in Set 1 and Set 2 were separated into four lists each (making eight different lists in total), with no more than one sentence from each set appearing in a single list. In each list, twenty-four experimental sentences were intermixed with forty-two fillers and presented in a randomized order to the participants. Approximately 30% of the fillers were sentences made to look similar to sluicing, as shown in (23), which served to reduce the participants expectation that all clauses that began with men jet vet ikke but I don t know were followed by sluicing remnants (see Martin and McElree 2011 for a similar strategy). (23) Janne har spist god vietnamesisk mat med kjøt men jeg vet Janne has eaten good Vietnamese food with meat but I know ikke meget. not much Janne has had good Vietnamese food with meat in it but I don t know 14

15 much. Yes/No questions were presented after approximately 70% of the trials (both experimental items and fillers) to verify whether participants were reading for comprehension. Average accuracy on these questions was above 95% and none of the participants scored less than 85% Procedure Participants eye movements were recorded with an SMI EyeLink high-speed eye tracker, with an angular resolution of 20 seconds of arc. The eye tracker was interfaced with a PC computer. All sentences were displayed in a single line on a 17-in. LCD monitor. Viewing was binocular, but only the right eye was recorded. Before the beginning of the experiment, participants were instructed to read for comprehension, and to do so at a normal rate. A calibration routine was performed afterward, and re-calibration was performed in between trials as needed. A key press triggered the presentation of the next sentence on the screen. The experiment was implemented using the SMI Experiment Center software. SMI BeGaze was used for initial data analysis Results and discussion I analyzed four regions in each critical sentence: the antecedent region, the correlate region, the remnant region, and the end region. The antecedent region consisted of the phrases preceding the correlate (Stig har fortalt in (20)). What I expected for this region were potentially inflated reading times in the conditions where remnants with prepositions were infrequent. The correlate region consisted of the PPs that served as remnants correlates (om en studentenfest). As before, I predicted inflated reading times in the conditions where remnants with prepositions were infrequent. The remnant region consisted of wh-phrases and prepositions, if present (om hvilken/hvilken). Inflated reading times in and/or regressive eye movement out of this region were also predicted for the conditions in which remnants with prepositions were infrequent. Finally, the end region was a spillover region consisting of the material that followed remnants (og jeg er likegyldig). Because the processing of the two types of remnants as part of ellipsis alternation remains unexplored, I keep both the predictions and the set of regions included open to various scenarios. For instance, the parser may only slow down upon encountering prepositions in remnants and then proceed, but it may also return to and re-fixate previous parts of the sentence upon encountering such prepositions. Among the measures computed were first pass time (or gaze duration), total fixation duration, go-past time, and percent regressions. The first measure 15

16 is assumed to reveal temporary parsing difficulty, that is, difficulty that merely slows the parser down rather than prevent it from computing a coherent sentence representation (Staub 2010). First pass time is the total time spent on a word or region before moving off of it for the first time (if there is only one fixation on a word or region, then first fixation duration and first pass time have the same value). Total fixation duration is the sum total of all fixations on a word or region, including the times the eyes return to it in order to re-read (parts of) it. Go-past time is the time spent on a word or region before moving off of it to the right, including all regressive eye movements to the earlier regions of the sentence. All these measures were computed on condition that no words were skipped. Regressive eye movements may signal more serious parsing difficulty that cannot be resolved without re-reading parts of the sentence (Staub 2010). Recall from section 3 that regressive eye movements have been reported for comprehenders who encounter material violating their expectations about the incoming structure, which they compute incrementally. It is possible that the sight of prepositions in remnants will trigger regressive eye movements if the prepositions conflict with expectations about what the incoming structure should be. The percent regressions measure was based on (1) the percentage of trials where the eyes moved backward rather than forward after leaving a word or region (regressions out). Prior to all data analysis, the following standard procedures were used. I first removed 2% of the sentences due to track losses. Fixations of less than 80 ms that fell within one character of the neighboring fixation (previous or subsequent) were incorporated into this neighboring fixation. Fixations of less than 40 ms that fell within three characters of the neighboring fixation were incorporated into this fixation. I then computed residual reading times for each word in both the experimental sentences and fillers: for each participant, I regressed log-transformed reading times (I logged raw reading times to normalize the data) against word length and then subtracted the predicted reading times from the log-transformed reading times. 7 This is a common procedure for experimental items in which regions of interest differ in length, because raw reading times are well known to be affected by word length and so may mask the influence of factors being investigated (Ferreira and Clifton 1986, Kennison and Gordon 1997, Hofmeister 2011). In the current data, the remnant region 7 The inclusion of both experimental items and fillers in the computation of the residual reading times avoids the risk that the experimental manipulations (phrasal informativity and absence/presence of prepositions in remnants) are collinear with word/region length. If the experimental items alone were the basis on which to estimate the effect of word length, they would fail to provide a reliable estimate of this effect (Hofmeister 2011). 16

17 differs between conditions, and the correlate region does, too, where phrasal informativity is involved. As the last step, I removed residual reading times that were more than 2.5 standard deviations from the mean at each word for each critical sentence. All of these procedures resulted in the loss of 4.1% of the data. For each measure on each region, I fitted a linear mixed-effects model to the data. The fixed factors in the models were the type of remnant (with or without prepositions) and correlate informativity (indefinite pronoun or NP), both of which follow directly from the hypotheses tested in this experiment. Besides these factors, I treated item order as a fixed factor as well due to its potential effects on the speed with which participants read. Bresnan and Ford (2010) note that continuous exposure to experimental items may speed participants up over the course of the experiment, but fatigue may also slow them down. The final fixed factor was reading times at the immediately preceding word. Because the antecedent region was not preceded by any words, I used this factor only in the models for three regions. The relevance of this factor is seen most clearly in the remnant region, which differs between conditions in terms of what its first word is (either a wh-phrase or a preposition). It is possible, for example, that participants preview prepositions during their fixation on the immediately preceding word, which affects the time spent on these prepositions when they are actually fixated. Each of the models included three random factors. These factors were controls for items, participants, and participants response to item order. Items and participants are commonly included in mixed-effects models, because different items may elicit different responses from participants, and participants may differ in how they respond to the same set of items. In addition, different participants may react differently to item order such as slow down or speed up necessitating inclusion of a random slope for this factor in the model (Bresnan and Ford 2010). I report the results of the analyses separately for each region below. Differences among conditions are treated as significant at the.05 level. Antecedent region No differences that approached significance were observed in this region. If there had been a processing difficulty here it could have been manifested by inflated reading times as the result of increased regressions made into this region. No such difficulty in fact appeared. Correlate region There was no hint of processing difficulty in the shape of inflated reading times on this region. Remnant region There was no hint of first pass time or total fixation duration differences between remnants with and without prepositions in this region. However, the go-past time differed significantly between remnants with prepositions and remnants without prepositions for the Set 2 items. The go- 17

18 Table 1: Mean residual go-past time for the remnant region (with standard deviations) in milliseconds Condition Residual go-past time Preposition absent (Set 2) -11.8(104) Preposition present (Set 2) 42.9 (131) Preposition present & skipped (Set 2) -36.5(133) Preposition absent (Set 1) (121) Preposition present (Set 1) 24.7 (144) past time was longer for remnants with prepositions than for remnants without prepositions (β = 48.83, SE = 2.17, t = 2.107, p <.04). There was no difference in go-past time between the presence and absence of prepositions if they were skipped on first pass reading for the same items (β = 11.85, SE = 40.17, t = 0.29, p =.76). Table 1 gives mean residual go-past time for the remnant region. The percent regressions measure revealed a reliable difference between remnants with and without prepositions for the Set 2 items on condition that the prepositions were fixated if present. More regressions were launched out of this region for remnants with prepositions than for remnants without prepositions (β = 15.22, SE =.07, t = 2.024, p <.05). This difference remained significant when only regressions on the first pass through this region were analyzed (β = 19.35, SE =.10, t = 2.062, p <.05). End region No significant differences were observed on any measure in this region, suggesting that any processing difficulty was resolved by the time the parser reached this region. Notably, additional analysis of regressions on the first pass through this region revealed that more regressions were launched for remnants with prepositions than for remnants without prepositions for the Set 2 items (β =.063, SE =.18, t =.347, p =.723). There was also a numerical trend for fewer regressions to be launched on the first pass when remnants with prepositions had noninformative correlates than when they had informative correlates (β =.18, SE = 3.48, t = 0.503, p =.576). However, neither of these trends approached significance. Thus far, the results indicate quite clearly that remnants with prepositions do not induce any temporary processing difficulty. We saw evidence for the second type of processing difficulty, where the parser makes increased regressive eye movements to re-read the earlier parts of the sentence. These increased regressions were observed exactly for those items where prepositions were least common in the remnants. To better understand what these results are telling us about the processing of instances of ellipsis alternation, I now turn to the second experiment, which used the same experimental items and fillers in an 18

19 acceptability judgment study. Keeping the experimental items constant across Experiment 1and 2 is a strategy allowing me to directly compare speakers s reaction to these items. 4.2 Experiment 2 For this experiment, I used the same eight lists of experimental items and fillers as before. Eighty University of Stavanger students (all monolingual speakers of Norwegian), who did not participate in the eye movement study, took part in this experiment. They rated the sentences on a 7-point scale, in which 7 was designated as Fully acceptable and 1 as Completely unacceptable. Participants ratings were standardized for statistical analysis and treated as the dependent variable in linear mixed-effects models of the data. The models included random intercepts for items and subjects and two fixed factors: absence/presence of prepositions in remnants and correlate informativity. The items in which prepositions were semantically dependent on verbs were analyzed separately from the items in which prepositions and verbs were semantically independent. The results are discussed below Results and discussion There was a significant difference in ratings between remnants with prepositions and remnants without prepositions. This difference was observed in the Set 2 items: remnants with prepositions received significantly lower ratings than remnants without prepositions (β = 17.74, SE = 8.53, t = 2.079, p <.04). There was no statistically significant evidence that remnants with prepositions were more acceptable with noninformative correlates than with informative ones in these items, although I observed a trend in the predicted direction (β = 8.39, SE = 6.26, t = 1.436, p =.153). Ratings for the two kinds of remnants did not differ in the Set 1 items (β = 17.84, SE = 20.70, t =.732, p <.465), and nor did correlate informativity interact with type of remnant in these items (β = 4.93, SE = 19.30, t =.235, p <.815). The results of this experiment are entirely consistent with the pattern of regressions observed in Experiment 1. The effect of semantic dependency between prepositions and verbs was seen in the go past time on the remnant region and regressions out of remnants with prepositions in the dependent items and in lower ratings for remnants with prepositions in these items. For the independent items, there were no differences either in regressions out of the two types of remnants or in ratings for them. 19

20 4.3 Experiment 3 The results of the preceding experiments suggest that the way a remnant is processed and rated is not independent of the location of its antecedent. It is possible for the parser to tease apart a preposition that is semantically dependent on a verb from one that is not when it reaches the remnant only after it has first processed the antecedent. If the antecedent was located after the remnant, this would be impossible. One way to test the hypothesis that remnants are processed and rated differently, depending on where their antecedents are located, is by comparing the kind of sluicing we have seen so far (let us call it regular sluicing) with reverse sluicing, as shown in (24). 8 (24) Jeg vet ikke for hvilken/hvilken, men Magnus har interessert I know not for which/which but Magnus has interested seg for en stein. REFL for a stone I don t know in which/which but Magnus has been interested in a stone. In reverse sluicing, the remnant appears before its antecedent and hence, we would intuitively expect absence or presence of a preposition to have a very different effect on the parser than it does in regular sluicing. Nykiel (2013) provides evidence that more informative correlates co-occurring with remnants without prepositions do not affect acceptability ratings in reverse sluicing. As discussed in section 2, a preference for remnants without prepositions to be paired with more informative correlates is evident in regular sluicing. No such preference emerges in reverse sluicing. Further, remnants with prepositions are consistently rated better than remnants without prepositions, a pattern that is not observed for regular sluicing in the same experiment. Nykiel (2013) attributes these differences between regular and reverse sluicing to the relationship between a remnant and its correlate, such that the remnant serves to retrieve the preceding correlate by providing retrieval cues required for this process. If the order of the remnant and correlate is reversed, the remnant no longer provides retrieval cues for its correlate, but has to be integrated into the incoming antecedent. We would expect, given this evidence, that a remnant with a preposition offers more specific cues as to its function in the structure of the antecedent and hence, the antecedent may be processed faster when it follows such a remnant. We would also expect that the way the rem- 8 For discussion of reverse sluicing, see Giannakidou and Merchant (1998), Coppock (2001), and Gullifer (2004). 20