Early Morphological Development

Transcription

1 Early Morphological Development Morphology is the aspect of language concerned with the rules governing change in word meaning. Morphological development is analyzed by computing a child s Mean Length of Utterance (MLU). Usually, a sample of 50 to 100 utterances is analyzed to draw conclusions about the child s overall production. Each word a child produces is broken down into morphemes. A morpheme is the smallest, indivisible unit of meaning. For example, the word walk is one morpheme, while walked is two morphemes: Walk carries its own meaning ed signifies past tense. Young children often combine words to convey one meaning or idea. Consequently, words such as gonna count as one morpheme. As adults, we underst that gonna really consists of both going to, each having meaning. After counting the morphemes for each of the child s utterances, they are totaled divided by the total number of utterances. The formula is as follows: MLU= Total number of morphemes Total number of utterances A child s MLU typically corresponds closely to their age. Roger Brown described five stages of language development based on MLU. The following table outlines typical MLU development: Stage MLU Approximate Age (In Months) I II III IV V V Source: Compiled form Brown (1973)

2 Morphological acquisition is best outlined by Brown s Fourteen Grammatical Morphemes. The chart below details at what age each morpheme typically emerges. Morpheme Example Age of Mastery* (In Months) Present Progressive ing Mommy driving In Ball in cup On Doggie on sofa Regular plural -s Kitties eat my ice cream Forms: /s/, /z/ /iz/ Cats, Dogs, Classes, Wishes Irregular past Came, fell, broke, sat, went Possessive s Mommy s balloon broke Forms: /s/, /s/ /iz/ as in regular plural Uncontractible copula He is (Verb to be as main verb) (Response to Who is sick?) Articles I see a kitty Regular past -ed Mommy pulled the wagon Forms: /d/, /t/, /Id/ Pulled, Walked, Glided Regular third person -s Kathy hits Forms: /s/, /z/, /iz/ Irregular third person Does, has Uncontractible auxiliary He is (Response to Who is wearing your hat? ) Contractible copula Man s big Man is big Contractible auxiliary Daddy s eating Daddy is eating *Used correctly 90% of the time in obligatory contexts. Adapted from Bellugi & Brown (1964); R. Brown (1973); J. Miller (1981). Sentence forms begin to develop as early as 12 months of age. Sentences can take on several different forms, including declarative, negative, interrogative, embedded conjoined. The following table details the development of each:

3 Stage Early I (MLU: 1-1.5) Late I (MLU: 1.5-2) Early II (MLU: ) Late II (MLU: ) Early III (MLU: ) Late III (MLU:2.75-3) Age (In Months) Declarative Negative Interrogative Embedding Conjoining Agent + Single word-no, Yes/no Serial Action; all gone, gone naming asked with without Action+ rising object intonation on a single word; what where Subj. + Verb + Obj Subj. + Copula + Compl Basic subjectverb-object used by most children Subj. + aux. + verb + objet. Appears; auxiliary verb forms can, do have will be Auxiliary verb s with copula in subj. + aux. + copula + X No Not used interchangeably No, not, don t, can t used interchangeably; negative element placed between subject predicate. Won t s What doing? Where going? Earliest inversion s with copula in what/where + copula +subj Auxiliary verbs do, can will begin to n ; inversion of subject aux. verbs s in yes/no Aux. Verbs do, can, will in Prepositions in on Gonna, wanna, gotta etc. And s But, so, or if

4 Stage Early IV (MLU:3-3.5) Late IV (MLU: V (MLU: ) Post V (MLU:4.5+) Age (In Months) Declarative Negative Interrogative Embedding Conjoining Negative Inversion of Object nounphrase s auxiliary verb conjoining with subject in complements with auxiliary wh- with verbs s, verbs such as think, because guess show; s embedded wh Double Adds isn t, Inversion of Infinitive phrases auxiliary aren t copula at the verbs doesn t subject in ends of sentences in didn t yes/no subj. + aux. ; + aux.+ adds when verb + X how Indirect object s in subj. + aux. + verb + ind. obj. + obj. Adds wasn t, wouldn t, couldn t, shouldn t 47+ Adds indefinite forms nobody, no one, none nothing. Has difficulty with double negatives. Some adult like tag Questions other that one-word why. Relative Clauses Gerunds. Relative clauses attached to subject, embedding conjoining within the same sentence above an MLU of 5.0 Conjoining with if s; three clause declaratives conjoining with because s with when, but so beyond an MLU of 5.0

5 By age five, a child is able to use most of the major variations of the English language. The order that these varieties are acquired indicates a pattern of cognitive, social learning growth. Language continues to develop into early adulthood to include more sophisticated usage. For more on language development, consult the following resources: Adrian, A. (Ed.). (1995). Lingistics: an introduction to language communication. 4th ed. Cambridge, MA: MIT Press. Owens, R. (2001). Language development: an introduction. 5th ed. Needham Heights, MA: Allyn Bacon. Center for Speech Language Pathology