This special issue revisits a classic topic in linguistic theory, A-bar movement, applied to developing and bilingual grammars. We claim that A-bar movement, or filler-gap dependencies, is still the quintessential linguistic phenomenon to illustrate the interaction between the biological endowment, the experience with language (past and present),…

Westergaard's microcue account raises the question of the exact nature of language transfer in the acquisition of languages as well of how L1/Ln input interacts with the principles of universal grammar (UG) during processing. In order to consider in more detail the actual representation building, processing mechanisms that would be involved, her…

This provocative article raises many important issues that need to be addressed and in so doing will advance the fields of second language (L2) and third language (L3) acquisition in several important ways. Fundamental questions concerning multilingual development persist especially with respect to the role of Universal Grammar in this language…

In her keynote article advocating the Linguistic Proximity Model for third language (L3) acquisition, Westergaard (2021) presents several arguments against 'copying and restructuring' in nonnative language acquisition, mechanisms central to Schwartz and Sprouse's (1996) Full Transfer/Full Access model of second language (L2) acquisition. In this…

This commentary discusses the recent keynote article in "Second Language Research" by Westergaard (2021), which extends the Micro-cue Model to second language (L2) and third language (L3) acquisition. The commentary comments on such questions as: What makes a given property easy or hard to acquire? How do learners determine similarity?…

In this commentary, I suggest that it may be helpful to think about the formidable problem space that Westergaard's (2021) Linguistic Proximity Model seeks to address at the three levels of analysis that Marr (1982) famously proposed are needed to understand any complex cognitive system. I argue that at the computational level of analysis, where…

In this article, I argue that first language (L1), second language (L2) and third language (L3) acquisition are fundamentally the same process, based on learning by parsing. Both child and adult learners are sensitive to fine linguistic distinctions, and language development takes place in small steps. While the bulk of the article focuses on…

Grammar competition has been proposed as a model for second language (L2) acquisition. Variational Learning provides a framework within which to investigate the idea of grammar competition as the model requires a marriage of quantitative properties of the input with Universal Grammar. A diachronic variational model of grammar competition is…

A generative approach to language acquisition is no different from any other in assuming that target language input is crucial for language acquisition. This discussion note addresses the place of input in generative second language acquisition (SLA) research and the perception in the wider field of SLA research that generative SLA…

A significant body of theoretically motivated research has addressed the role of Universal Grammar (UG) in the nonnative acquisition of morphosyntax and properties of the syntax-semantics interface, but very little research has addressed the role of phonological principles of UG in nonnative language acquisition. Turkish has a regular and…

This article offers commentary that the Multiple Grammar (MG) language acquisition theory proposed by Luiz Amaral and Tom Roeper (A&R) in the present issue lacks elaboration of the psychological mechanisms at work in second language acquisition. Topics discussed include optionality in a speaker's grammar and the rules of verb position in…

This article reports the findings of a study in which we investigated the possible effects of word order on the acquisition of case marking. In linguistic typology (e.g. Greenberg, 1963) a very strong correlation has been shown between dominant SOV (subject object verb) word order and case marking. No such correlation exists for SVO (subject verb…

Amaral and Roeper (this issue; henceforth A&R) argue that all speakers -- regardless of whether monolingual or bilingual -- have multiple grammars in their mental language representations. They further claim that this simple assumption can explain many things: optionality in second language (L2) language behaviour, multilingualism, language…

Amaral & Roeper's Multiple Grammars (MG) proposal offers an appealingly simple way of thinking about the linguistic representations of bilingual speakers. This article presents a commentary on the MG language acquisition theory proposed by Luiz Amaral and Tom Roeper in this issue, focusing on the theory's implications for child…

Optionality is a central phenomenon in second language acquisition (SLA), for which any adequate theory must account. Amaral and Roeper (this issue; henceforth A&R) offer an appealing approach to it, using Roeper's Multiple Grammars Theory, which was created with first language in mind but which extends very naturally to SLA. They include…