An Acquisition Study Of Wh-Questions By English-Speaking Children

Language acquisition provides crucial evidence to test linguistics and learning theory as well as to explore the working mechanism of human mind. In the field of linguistics and language learning, two competing paradigms coexist. One is represented by Noam Chomsky and his followers, who advocate rule-based Universal Grammar in linguistic study and language innateness hypothesis in language acquisition study. Under this paradigm, the syntax system of all languages consists of innate principles and parameters, and syntax learning requires and only requires children to set the appropriate parameters for the specific languages they are exposed to. Under this framework, language production firstly makes use of the argument structures of the main verb in a sentence to project its D-structure, which then is transformed to S-structure. The result of these two operations is the grammatical sentence. The other paradigm is represented by cognitive linguistic theory and usage-based language learning models. This paradigm believes that language system consists of networks of constructions existing at multiple levels of concreteness and abstraction, and language acquisition is a process of learning constructions. This approach, believing that general cognitive capacity is sufficient for language learning, assumes no innate language-specific knowledge. It emphasizes the importance of input, language usage and their frequency in shaping language developmental process. Wh-questions form a good testing case for these two competing approaches, for universal grammar posits that the production of wh-questions should undergo two transformations: wh-movement and I to C movement while cognitive approach, believing that word order is directly specified in constructions, assumes no transformation operation in the production of wh-questions. The different assumption about language representation and production should predict different development process in the acquisition of wh-questions, which were investigated in this study by using CHILDES database. Four analyses are conducted.The first analysis investigates the distribution of wh-questions in child-directed speech. Previous studies found that questions comprise a substantial proportion of child-directed speech. However, until now, to my knowledge, the properties of wh-questions in CDS are still left uninvestigated. Therefore, the first task of this analysis is to investigate the distributions of wh-questions in CDS. Moreover, previous studies found that CDS is a distinctive speech style, which has special features. Thus, the second task of this analysis is to investigate whether wh-questions in CDS also have some special features. The investigation found that different wh-questions have different distributional patterns. The percentage of what questions, accounting for 60% of all wh-questions, remains stable throughout the study. Where and who questions are of high proportion at the beginning but show a decrease tendency over time, while how, when and why questions show exactly opposite developmental pattern, which are of low proportion at the beginning but show increase tendency with children's age. This distribution pattern indicates that CDS develops with the language development of children, for how, why and when questions are more complex than what, where, and who questions no matter in terms of linguistic structures or in terms of conceptual complexities. Furthermore, this analysis also found some wh-in-situ questions in CDS that is not attested in adult speech, which shows that in order to help children understand and respond to CDS, care-takers may even adjust their speech into the unconventional forms. These findings suggest that CDS may not be degenerated at all but rather may be fine-tuned to the language development of children.The second analysis investigates the distribution pattern of wh-questions in child speech. The acquisition of wh-questions generally conforms to the following order: what, where, who, why, how, when. This developmental pattern correlates to a substantial degree with input, in which what, where and who questions appears with high frequency at the beginning stage while why, how and when questions appears with high frequency only at later stage. Some wh-questions show U-shape developmental pattern. A conspicuous example is the development of why questions, which appears in great quantities at the age of 2.25 years old but is used less frequently afterwards. The underlying reason for this developmental pattern is that language use is closely connected with the conceptual development. Asking why questions requires the understanding of the concept of causal relationship. Different concepts are different in terms of their complexities, which require different time schedules to develop, which may in turn influence language acquisition. This analysis shows that language acquisition is influenced by input and factors such as the complexity of concept.The third analysis investigates whether children learn wh-movement rules during language learning process. If language learning is a process of setting parameters as nativists have suggested, the developmental sequences of wh-questions should mirror the production sequence specified in Universal Grammar, i.e. children should produce wh-in-situ questions first, after which, wh-questions undergoing wh-movement but not I to C movement would be produced, and only at the last stage, children could produced adult-like wh-questions. However, previous studies found that children place wh-words at the initial position of wh-questions, which is in conflict with the prediction. However, this finding is only incompatible with the assumption that Universal Grammar is available to children from very beginning. Different components of Universal Grammar could well be accessible to children at different developmental stages. If principles or parameters related to wh-questions production are not accessible to children only at very beginning, and the production of wh-questions at this stage entirely rely on memory-retrieval, it could explain why at very beginning children produce wh-questions with wh-words at the initial position. However, an investigation of this explanation shows that it is in conflict with the data. Furthermore, this analysis also found unconventional wh-questions with what is that/this construction, which is incompatible with the assumption that the production of sentences is first projected from the argument structures of verbs. They seem to be better accounted for with the frequency effect of what is that/this in input and output. Thus, these questions not only show the problematic nature of universal grammar, but also reveal that frequency plays an important role in language acquisition process.The fourth analysis investigates whether children learn I to C movement during language learning process. Under the framework of Universal Grammar, rules or principles operate on syntactic categories. Therefore, theoretically, if a child learns a rule, he should be able to apply it to all members of the category on which the rule operates. However, previous study found that in child speech, inverted and non-inverted wh-questions coexist, which suggest that I to C movements are not uniformly applied to all cases that should undergo movement. This finding is incongruent with rule-based learning theory. To remedy the theory, different properties among wh-words and auxiliaries are invoked to explain this divergence. Unfortunately, studies afterwards show that these explanations are also untenable when the inversion rates of different combinations of wh-words and auxiliaries are examined. However, inversion rates may not be a good index to examine these explanations, for these explanations may predict difference in acquisition orders rather than in inversion rates. Therefore, the first task of this analysis is to investigate the acquisition order of subject auxiliary inversion, and it is investigated against 90% correctness standard proposed by Brown (1973). The investigation found that the inversion of copula BE is acquired the first, and exhibits stage-like development; the auxiliary BE achieves a 90% inversion rate half a year later than copula BE, but it shows serious regression afterwards; the inversion rate of auxiliary DO increases gradually; and the inversion rate of modals fluctuates a lot due to the scarcity of related samples. These findings are exactly the opposite to Stromsford (1990) and Santelmann et al. (2002)'s proposal that inversion of copula BE is more difficult to acquire than the inversion of other auxiliaries under the framework of Universal Grammar. Cognitive linguistics believes that the coexistence of inverted and non-inverted wh-questions is better accounted for under the usage-based language learning models, which posits that subject auxiliary inversion is acquired by learning specific combinations of wh-word + auxiliary rather than by learning the rule of I to C movement. An investigation of this proposal shows that the inversion behaviors of copula BE and auxiliary BE with the same overt forms are different from each other. Although this finding is incompatible with the proposal, it is not in conflict with the usage-based language learning model itself. Under the usage-based model, a fundamental task of language acquisition is learning constructions. Copula BE and auxiliary BE appear in different constructions. Therefore, the different inversion behavior between copula and auxiliary BE is not unexpected for usage-based learning model.The results of these four analyses are more congruent with the usage-based language learning models than with rule-based Universal Grammar and language innateness hypothesis. This study found that CDS is not as degenerated as nativists have proposed. Rather it seems to be attuned to the language development of children, and sometimes care-takers even use unconventional expressions to help children understand and respond to the speech. Furthermore, this study did not find any evidences suggesting that children learn rules, let alone the rules of wh-movement or I to C movement, during language acquisition process. Moreover, the unconventional wh-questions discovered in this study suggest that sentence may not be the result of projection from the argument structure of verbs, which further calls into questions the sentence production framework of Universal Grammar. All in all, this study found that language learning process is a process of learning lexical frames or constructions, within which frequency effect plays a vital role.