In this paper I argue that cross-linguistic similarity in third language acquisition is determined by a structural hierarchy of contrastive phonological features. Such an approach allows us formalize a predictive notion of I-proximity which also provides an explanatory model of L2, and L3 phonological knowledge (represented in an integrated I-grammar). The metrics of phonological similarity (i.e., structural not acoustic) are analogous to morphosyntactic similarity in that both morphosyntactic and phonological approaches can compare the outcomes of parsing the L3 input by the L1 hierarchy and by the L2 hierarchy. From this starting point I propose a conservative, incremental learning theory to guide subsequent reconstruction of the L3 grammar. Under this model, it can be argued that phonology is part of Faculty of Language Narrow (FLN). The (gradient) phonetic material comes from outside the FLN but the linguistic computational system converts it to discrete abstract elements that can be manipulated by the learner.

中文翻译：

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使用对比层次结构将结构相似性形式化为 L3 音韵学中的 I-邻近性

在本文中，我认为第三语言习得中的跨语言相似性是由对比语音特征的结构层次决定的。这种方法使我们能够形式化 I-邻近性的预测概念，它还提供了 L2 和 L3 语音知识（以集成的 I-语法表示）的解释模型。语音相似性（即结构而非声学）的度量与形态句法相似性类似，因为形态句法和语音方法都可以比较通过 L1 层次结构和 L2 层次结构解析 L3 输入的结果。从这个出发点我提出了一种保守的增量学习理论来指导后续的 L3 语法重建。在这种模式下，可以说音系学是狭义语言学院（FLN）的一部分。（梯度）语音材料来自 FLN 外部，但语言计算系统将其转换为学习者可以操作的离散抽象元素。