In this short article I try to present a taxonomy of sources of difficulty, in particular complexity. I emphasize how these factors interact with each other and with individual differences and treatments, before illustrating some of these interactions and the methodological issues involved in studying them with examples from the empirical studies…

There is a growing theoretical, empirical, and methodological debate in the SLA field as to whether unawareness plays a role during attention to or processing of new incoming second language (L2) data. Indeed, studies that have methodologically addressed the construct of unawareness in their research designs offer both empirical support (e.g.,…

Goo and Mackey (this issue) outline several apparent design flaws in studies that have compared the impact of different types of corrective feedback (CF). Furthermore, they argue that SLA researchers should stop comparing recasts to other types of CF because they are inherently different kinds of phenomena. Our response to their article addresses…

This article reexamines Bley-Vroman's original (1990) and evolved fundamental difference hypothesis that argues that differences in path and endstate of first language acquisition and adult foreign language learning result from differences in the acquisition procedure (i.e., language faculty and cognitive strategies, respectively). The evolved…

Responds to Ellis (2002), which suggests the statistical structure of the linguistic environment is a crucial and relatively neglected variable in language learning. This approach makes three assumptions about cognition and language learning that are not universally shared. Describes a distributed, instance-based approach that retains key features…

Discusses frequency effects in language acquisition. Provides an example of how frequency may relate to grammatical judgments of nonnative speakers acquisition of multiple wh-questions. (Author/VWL)

Responds to Ellis (2002), which focuses on frequency in language processing, language use, and language acquisition. Suggests his findings are consistent with those of second language acquisition researchers working with a variationist framework. Provides a brief overview of this research area and describes a psycholinguistic model of language…

Introduces the concept of lexical unit as proposed by Cruse (1986) in the context of second language vocabulary learning to replace the notion of "word." Defines the concept in terms of lexical semantics and applies it to the task of learning a second language. Describes studies in which the learning of different types of lexical units is…

Ways are described in which studies on grammaticalization in second-language learning are a challenge for second-language acquisition theory. This article introduces four articles on grammaticalization. (21 references) (LB)

Refutes the assumption on which most second language research is based--that language is intended by its speakers to transfer information to some interlocutor--by responding to Tomlin's paper in the same journal, "The Treatment of Foreground-Background Information in the On-Line Descriptive Discourse of Second Language Learners."

In response to Ellis (2002), which focuses on frequency in language processing, language use, and language acquisition, this article argues in favor of a role for frequency in several areas of second language acquisition, including interactional input and output and speech processing. Also discusses areas where L2 acquisition appears to proceed…

An author reacts to a series of responses written in regard to an earlier article by the author on frequency in language processing, language use, and language acquisition. Addresses a number of issues raised in the responses and concludes by emphasizing that language acquisition is a process of dynamic emergence and learners' language is a…

Discusses dependence and frequency data in second language acquisition research and investigates the violation of the "independent observation" assumption as well as the effect of including interaction terms in frequency data analysis. Argues in favor of using multifactorial frequency data analyses over multiple chi-squares to take into account…

Responds to an article on top-down versus bottom-up analyses of interlanguage data in second language acquisition research that argues in favor of using multifactorial frequency data analyses over multiple chi-squares to take into account dependence and interaction of the frequency data. (Author/VWL)

Examines Tomlin and Villa's (1994) analysis of attention and Leow's (1998) attempt to operationalize this model. Argues that Leow's efforts to provide empirical support for the model fall short of that goal. (Author/VWL)