Doctoral Dissertation Research: The role of input reliability and shared variability on the acquisition of linguistic variation

为了学习他们的第一语言，儿童需要学习语言的变化，因为系统的变化存在于语言结构的各个层面，是语言知识的一个组成部分。举一个英语的例子，说话者有时会把以-ing结尾的单词发成-in'（例如，工作对工作）取决于语言内部因素（例如，-in'在分词中的使用频率比在名词如' morning '中的使用频率更高）以及外部（例如，-in'在非正式会话中比在正式会话中更常用）。学习这种概率模式是一个艰巨的挑战，因为孩子们必须弄清楚交替中的变量，与交替相关的因素，与每个变量相关的相对概率率等等。解释这一过程对于任何语言习得的解释都是至关重要的，但只有少数研究直接调查了儿童对变异的习得。虽然新出现的证据表明，儿童确实会获得变异，但我们也知道，他们倾向于改变语言输入，使其更加规则--这个过程通常被称为规则化。两者合计，出现了一个悖论：儿童显然学习和匹配概率语言变化在某些情况下，但在其他规则化这种变化。孩子们什么时候会匹配变异，什么时候会规则化？虽然以前的研究确定了一个条件反射因素的存在，输入的数量和频率的交替上下文作为重要的因素，这个问题仍然在很大程度上未被探索。本文研究了语言输入的可靠性和变异性是否在说话者之间共享对学习者概率变异匹配的影响。具体来说，儿童学习者接触到微型语言，旨在包含变化，和因素被操纵一次，以确定他们是否为学习者提供重要的线索，是否要正规化或学习的变化。这项研究有助于进一步了解儿童如何平衡两个重要的学习机制，在嘈杂的信号中找到规律性，同时保留语言的有意义的概率方面，从而深入了解语言习得的认知机制。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

To learn their first language, children need to learn variation in the language, as systematic variation is present at all levels of language structure and is an integral part of linguistic knowledge. To give an example in English, speakers sometimes pronounce words ending in -ing with -in’ (e.g., working vs. workin’) depending on language-internal factors (e.g., -in’ is used more frequently in participles than in nouns like ‘morning’) as well as external (e.g., -in’ is used more frequently in casual conversational context than formal). To learn such probabilistic patterns is a daunting challenge as children must figure out variants in alternation, factors relevant to the alternation, relative probabilistic rates associated with each variant and more. Accounting for this process is crucial to any account of language acquisition, yet only a handful of studies have directly investigated children’s acquisition of variation. While emergent evidence suggests that children do acquire variation, we also know they tend to change their language input and make it more regular — a process often referred to as regularization. Taken together, a paradox arises: children apparently learn and match probabilistic linguistic variation under some circumstances but regularize such variation under others. When would children match variation and when would they regularize? While previous research identified the presence of a conditioning factor, quantity of input and frequency of alternating context as important factors, this question remains largely under-explored. This dissertation investigates the effects of reliability of language input and whether variability is shared across speakers on learners' matching of probabilistic variation. Specifically, child learners are exposed to miniature languages designed to contain variation, and factors are manipulated one at a time to determine whether they provide learners with important cues with respect to whether to regularize or learn the variation. This research contributes to a further understanding of how children balance two important learning mechanisms to find regularity despite noisy signals while preserving meaningful probabilistic aspects of the language, thus yielding insight into cognitive mechanisms underlying language acquisition.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.