Syntax Acquisition: Innate Vs. input-driven Accounts
To look into the claims of what and how much is innate and is input driven, language researchers have, time and again, posited some basic questions. In this article, we will discuss some of them.
Why do not children generate overly general grammars along with structural independent mistakes?
Focusing on the nature of linguistic operations, we can ask why children do not utter sentences that are inconsistent with the structural dependencies of language and possibly end up with an overly general grammar based on the input they receive. Given the impoverished linguistic data that child receives; the child never builds utterances that are independent of the structure of the target language (Chomsky, 1971). Put in simple words, the mistakes the child makes still adhere to the basic structure of the language. The child will never make certain kinds of errors.
The nativists say this is possible because these syntactic constraints are set innately and that allow the child to make certain constructions and puts restrictions on the others. If that were not true, then the relevant linguistic input available has to be sufficient to ensure that every child converges on a grammar that conforms to structure-dependent operations, which does not happen (Legate and Yang, 2002).
The No-Negative and No-Decisive positive evidence problem
>A strong argument against empiricists comes from the no-evidence problem, which is a direct consequence of poverty of stimulus. This means that the child masters language syntax in the presence of impoverished linguistic input. But, the question of no evidence has been itself questioned by linguists who adopt an experience-dependent approach (Cowie, 1999). Chomsky and other nativists make it clear, however, that they do not challenge the existence of evidence or the child’s capacity to use it, but the robustness of the evidence instead. At any given time, it is not possible to have all positive evidence. In simple terms, positive evidence is there, but is not enough. Besides this, the negative evidence is almost always missing. The nativist’s proposal of innately set constraints can possibly explain acquisition of syntax in the absence of decisive evidence.
Early and time-bound emergence of linguistic structures
Another major hallmark of innate constraints is their Early emergence (Crain, 1991). However, not all syntactic structures appear at the same time, and that too at a very early stage. Empiricists say that this is because enough experience is not available at all stages, and so development of different syntactic structures occurs as and when the experience is sufficient. But the nativists argue that just as some features of biological development appear during and after maturation, some linguistic features can too appear after a certain stage (Borer and Wexler, 1987).
A key feature of language acquisition is that irrespective of other factors, striking commonalities are observed in the course of development of syntax in children, that too from a very early age. In fact, the sequence of syntactic stages is almost predictable due to this fact (Brown, 1973 and De Villiers, 1978).
To begin with, one-word utterances begin at the age of one year. By the time the child reaches twenty months, she has already acquired over fifty-word vocabulary and after that, she begins entering a two-word stage. Till about three years, the child speech resembles telegraphic speech, mostly comprising of content words. Syntactic complexity begins after three years, and, at the age of four years, child speech resembles adult speech. The time period between five to ten years is when the child masters infrequent constructions and sorts out lexical exceptions.
Are there any Syntactic Patterns in Child Speech?
Interestingly, pivot patterns have been observed in early syntax of English speaking children (Braine, 1963). Few words always acted like pivots, appearing either at the end or at the beginning of the utterances. These included words like some, more, all, etc. These were called as pivots. Other words would occur anywhere in the utterance. Words like mommy, daddy, etc. constitute the other category. Such a pattern alludes to the fact that child speech is not random or devoid of patterns.
In fact, it is a strongly held view that child speech confirms to syntactic patterns of the target language very early in the development of syntax. Hence, whether the language is configurational or non-configurational type, left branched or right branched, etc. should be evident even at a two-word stage. In experiments on English speaking children aged 3-4 years, positive evidence for this was reported for English, which is a left-branching, configurational language (Bavin and Shoppin, 1985).
Child speech is not exactly like adult speech. Subject-less constructions are frequently observed in speech of children speaking languages where pro-drop is not allowed. Children do not hear subject-less sentences from adults speaking the same language, and a question arises why do they say what they never hear. A refuge to the innately set principles and parameters theory becomes important here, as the experience-driven accounts do not explain why even without any positive evidence in the environment the child is lead to utter subject-less constructions.
In this regard, however, some empiricists have claimed that the child’s grammar is incorrect to begin with, but it soon gets attuned to phrase structure patterns of their language by requisite experience (Tager Flusberg et al, 1982, Lust and Chien, 1984, Clahsen and Muysken, 1986). As we see, both the principles and parameters approach and experience-driven accounts explain the case of occurrence of subject-less sentences in early syntax of languages without pro-drop, albeit in different ways.
If we go with the principles and parameters approach, then we will have to ask when exactly does the sensitivity to parameter switches for syntactic structures begin and whether this sensitivity is different for different structures. It is also important to ask if there is an order to of tuning of these parameter switches and if this order is universal. To test, the experience-driven accounts for this phenomenon, we will have to look at child language data for other such structures. If child syntax is incorrect to begin with, then she should fail or perform poorly in truth value judgment tasks in their language at that given stage.
It is important to know that assuming one extreme position or one camp is futile here. The debate should be on how much is innate and how much is taken from the input, but not whether one exists or the other. While taking the empiricist’s position, one has to acknowledge that there is definitely some innate capacity in a human child to acquire language. And while studying innate constraints, the role of input cannot be overlooked.
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