Language Acquisition: Morphological Development PDF

1. Morphological development As is the case with the sound pattern of language and with vocabulary, the details of morphological structure emerge over a period of several years. Initially, affixes are systematically absent and most words consist of a single root morphem...

1. Morphological development As is the case with the sound pattern of language and with vocabulary, the details of morphological structure emerge over a period of several years. Initially, affixes are systematically absent and most words consist of a single root morpheme. 1.1 Overgeneralization or Overregularization Inflectional suffixes: modify a word to express grammatical relationships without changing its meaning or category Many common words have IRREGULAR INFLECTION in English (went as past tense of go, ran... run, men… man). Children sometimes begin by simply memorizing inflected words on a case-by-case basis without regard for general patterns or rules. As a result, they may INITIALLY use irregular forms such as men and ran correctly. However, when they subsequently observe the generality of -s as a plural marker and -ed as a past tense marker (usually around age two and a half), they sometimes use these suffixes for the IRREGULAR FORMS -producing words such as mans and ruined. (Errors that result from the overly broad application of a rule are called overgeneralizations or overregularizations.) Even occasional mixed forms such as felled, a blend of fell and falled, may occur during this period. One of the best indications that children have mastered an inflectional rule comes from their ability to apply it to forms they have not heard before. Although inflectional overgeneralization is very noticeable in young children's speech and can last into the school years, it doesn't affect all irregular verbs all the time. In fact, preschool children seem to overregularize verbs less than 25 % of the time at any point in development. This suggests that the overgeneralization errors observed in early speech reflect lapses in accessing the appropriate irregular form from the lexicon rather than the failure to learn irregular forms per se. 1.2 A Developmental Sequence An important result of early work on child language was the discovery that the development of bound morphemes and functional categories (such as determiners and auxiliaries) takes place in an orderly fashion that is quite similar across children. In a pioneering study of three children between the ages of twenty and thirty-six months, the developmental sequence was found to be typical. 1. -ing 2. Plural -s 3. Possessive s 4. The, a 5. Past tense -ed 6. Third person singular s 7. Auxiliary be The developmental sequence seems to be at least partly independent of the frequency with which the various morphemes occur in adult speech. 1. The, a 2. -ing 3. Plural s 4. auxiliary be 5. Possessive s 6. 3rd person singular s 7. Past tense -ed This shows THAT FREQUENCY BY ITSELF CANNOT EXPLAIN DEVELOPMENTAL ORDER, although it may have some role to play in conjunction with other factors. (It's also clear that pronunciation by itself is not decisive either, since the three -s morphemes are acquired at different times.) What, then, determines the order of acquisition of non- lexical categories and bound morphemes? Research on a variety of languages suggests that several factors are involved……………..6 FACTORS 1. Frequent occurrence, especially in utterance-final position Children show a greater tendency to notice and remember elements that occur at the END of the utterance than those found in any other position. 2. Syllabicity Children seem to take greater notice of morphemes such as -ing, which can CONSTITUTE SYLLABLES on their own, than the plural or possessive suffix -'s, whose principal allomorphs (/-s/ and /-z/) are single consonants. 3. Absence of homophony Whereas the word the functions only as a determiner in English, the suffix -s can be used to mark any one of three things: plural number in nouns, third-person singular in verbs, or possession. The resulting complication in the relationship between form and meaning may impede acquisition. 4. Few or no exceptions in the way it is used Whereas all singular nouns form the possessive with 's, not all verbs use -ed to mark the past tense (saw, read, drove). Such exceptions hinder the language acquisition process. 5. Allomorphic invariance Whereas the affix -ing has the same form for all verbs, the past tense ending -ed has three allomorphs: /-t/ for verbs such as chase, /-d/ for forms such as love, and /-ǝd/ for verbs such as decide. This type of allomorphic variation, which also occurs with the plural, possessive, and third-person singular affixes in English, slows morphological development. 6. Clearly discernible semantic function Whereas morphemes such as plural-s express easily identifiable meanings, some morphemes (such as the third-person singular -s, as in She works hard) make no obvious contribution to the meaning of the sentence. Acquisition of this latter type of morpheme is relatively slow. 1.3 Word formation processes The major word formation processes in English-DERIVATION AND COMPOUNDING- both emerge early in the acquisition of English. Derivational suffixes change the meaning of words: “er” added to the verb “sing”: noun “singer” The first derivational suffixes to show up in children's speech are the ones that are most common in the adult language: Children exhibit a propensity for forming compounds, especially of the N-N type. When asked "What would you call a boy who rips paper?", they don't hesitate to respond "a paper ripper." However, some of the compounds found in the spontaneous speech of three- and four-year-olds do not follow the usual pattern for English compounds (e.g., the verb-noun pattern "open man for 'someone who opens things' and cutter grass for 'grass cutter'), but these disappear by age five. Other early compounds have the right structure but are inappropriate because English already has words with the intended meaning (see Table 9.15).  2. Syntactical development Like phonological and morphological development, the emergence of syntactic structure takes place in an orderly manner and reveals much about the nature of the language acquisition process. 2.1 The One-Word Stage As noted earlier, children begin to produce one-word utterances between the ages of twelve and eighteen months. A basic property of these one-word utterances is that they can be used to express the type of meaning that is associated with an entire sentence in adult speech. Thus, a child might use the word: dada to assert 'I see Daddy', more to mean 'Give me more juice', Such utterances are called holophrases (literally 'whole sentences'). and up to mean 'I want up'. THEY CHOOSE THE MOST INFORMATIVE WORD: juice to mean “I want juice”, instead of want since juice is more informative doll to mean “I see a doll” holophrases Comprehension appears to be considerably in advance of production in the one-word stage, and children are able to understand many multiword utterances during this period. 2.2 The two-word stage Within a few months of their first one-word utterances, children begin to produce two-word mini-sentences. Table 9.17 provides a sampling of these utterances and the types of meaning they are commonly used to express. (Although these examples are from English, similar patterns are found in the early development of all languages.) It is unclear whether children have acquired syntactic categories such as noun, verb, and adjective at this point in their development. This is because the markers that help distinguish among syntactic categories in adult English (e.g., inflection such as the past tense suffix and functional categories such as determiners and auxiliary verbs) are absent during this period. the relative shortness of the utterances produced during the two-word stage means that the positional differences associated with category distinctions in adult speech are often not manifested. Thus, words such as busy (an adjective in adult speech) and push (a verb) dgmay appear in identical patterns. Mommy busy. Mommy push. While this does not show that children lack syntactic categories, it makes it difficult to demonstrate that they possess them. A notable feature of children's two-word utterances is that they almost always exhibit the appropriate word order, and there is some reason to think that learners have a general word order rule by the time they are three years old. Not only do they use the right subject-verb-direct object order in their own speech, they are reluctant to abandon this pattern 2.3 the telegraphic stage After a period of several months during which their speech is largely limited to one- and two-word utterances, children begin to produce longer and more complex grammatical structures, drawing on an ever-growing store of words. As illustrated in the sentences in example 8, a defining feature of these patterns is the frequent absence of bound morphemes and nonlexical categories. Chair broken. This stage is characterized by the emergence of quite elaborate types of phrase structure. For example, phrases consisting of a head and a complement (like book, ride Daddy like book. bus, show mommy), phrases that include a modifier (today, good) What her name? Language development from this point onward is rapid. Man ride bus today. Children move from relative primitive two-and three-word utterances at the beginning of Car make noise. the telegraphic stage to a broad range of morphologically and syntactically intricate sentence types. Me wanna show Mommy. What doing? I don’t want to go to bed again. I good boy. 2.4 Later development Children continue to acquire the complex grammar that underlies adult linguistic competence, including the operations that move various words and phrases to nonbasic positions in the sentence. Yes-no questions The later development is marked by their ability to form yes-no questions using rising intonation alone, without auxiliary verbs. For example, a child might ask "Daddy go?" instead of "Is Daddy going?". However, when auxiliary verbs are learned, children often place auxiliary verbs BEFORE the subject or use them REDUNDANTLY within sentences. For instance, they might say "Will she will go?". Inversion is easier in yes-no questions, where it is the only movement operation WH- questions Wh-questions (who, what, where, why) emerge between the ages of 2 and 4. Nevertheless, children may face challenges with inversion in these questions; for example, they might say "What you want?" instead of "What do you want?" Inversion: In wh- questions, the “wh word” must also be moved. Children’s speech shows the effect of moving the wh- word but not the auxiliary verb. Example: What I did yesterday? Where I should sleep? Why that boy is looking at us? 2.5. The interpretation of sentence structure As children's language skills continue to develop, so does their ability to interpret sentence structures accurately. One fascinating aspect is their understanding of passive constructions. Children often expect that the first noun phrase (NP) in a passive sentence will refer to the agent performing the action—a phenomenon known as the Canonical Sentence Strategy (agent-action-undergoer). For example, when presented with "The ball was kicked by the boy," they may initially interpret it as if "the ball" is the one performing the action. NOT ONLY IS IMPORTANT WORD ORDER, BUT ALSO FORM OF THE VERB AND THE PRESENCE OF BY (The first NP refers to the undergoer rather than the agent) Moreover, children's use of pronouns and reflexives typically demonstrates an emerging proficiency in language. While they generally use pronouns correctly—such as saying "I want it"—occasional errors do occur. For instance, a child might say "Him went to the store," reflecting their ongoing process of mastering grammatical rules and conventions.  3. What makes language acquisition possible? It is relatively easy to describe what takes place during these years, but it is much more difficult to explain how it happens. Some factors that may contribute to an eventual understanding of how the language acquisition process works are mentioned: 3.1 The role of experience Children need to be exposed to language; they need to observe it being used by those around them as often as possible. The consequences of limited exposure to speech in a very striking manner: children who hear a lot of language develop much faster than children who do not: High level exposure to language: average vocabulary size at age 30 months; 766 words Low level exposure to language: average vocabulary size at age 30 months: 357 words They not only know twice as many words at age 30 months, but also do significantly better in school. Therefore, the best thing parents and caregivers can do is speak to their children. Need of Special adjustments to parents/caregivers’ speech when talking to their children? Probably not, although many subconsciously make some changes, producing what is sometimes called motherese or caregiver speech. Make it easier for children to pick out words and learn their pronunciation. Acquisition of meaning because of the here and now (especially the child’s, surroundings, activities, and needs) Many other features of caregiver speech seem not to affect child language. As mentioned earlier, the relative frequency OF BOUND MORPHEMES and NONLEXICAL CATEGORIES in caregiver speech does not determine their order of acquisition… SEE THE DEVELOPMENTAL SEQUENCE… Children do not learn by imitating. Not only do children tend not to repeat the speech of others, they are typically unable to imitate structures that they have not yet learned. For instance, children who have not yet started to invert the auxiliary verb and the subject in questions will avoid INVERSION in their imitations. 3.2 The role of feedback It is sometimes suggested that parents help their children learn the language by correcting their “mistakes”. However, studies mention that parents tend to be more concerned with the truth of children’s utterances than with their grammaticality Child: Mama isn’t a boy, he’s a girl! Mother: That’s right When adults attempt to correct children’s grammatical errors, their efforts often have little effect. However, some research suggests that subtler forms of feedback may have a role to play in the language acquisition process. Recast: adult often respond to children’s utterance by repeating it, making adjustments to its form or content. Recasts provide children with potentially useful information e.g adding “is”, changing him to he, etc. However, parents usually don’t correct errors, and sometimes reformulate children’s grammatical utterances Child: the dog is barking. Mother: Yes, he is barking at the kitty. 3.3. The role of cognitive development Because there are dramatic changes in both linguistic and nonlinguistic abilities during the first years of life, it is tempting to think that the two are somehow linked. Yet there is considerable evidence to suggest that language acquisition is to a large extent independent of other types of cognitive development. One such piece of evidence comes from the study of individuals whose general cognitive development is deficient but whose language is highly developed. Some cases of dissociation between language and cognitive development show a poor performance on nonlinguistic tasks but a high level of language development. For example, Rick who at age 15 performed so poorly on a variety of nonlinguistic tasks but his speech manifests considerable syntactic and morphological sophistication (appropriate use of affixes, nonlexical categories, and word order). Christopher (adult) who can read, write, and communicate in about 20 languages, but has trouble with addition (can handle 12 +13, but no 14+19), is bad at drawing, cant figure out how tic-tac-toe works, and is unable to take care of himself. At the same time, there are also documented cases of people whose IQ is within the normal range but who nonetheless have great difficulty with inflection for the past tense and plural. AGAIN. Inflectional morphemes (add suffixes but not alter word category: e.g: phone (verb in simple present) phoned (simple past) cookie (sing. noun) cookies (pl. noun) Cases studies such as these suggest that certain aspects of language (in particular morphology and syntax) are INDEPENDENT of nonlinguistic types of cognitive development. 3.4 The role of inborn knowledge IS THERE A CRITICAL PERIOD?