DO MEASURES OF INDIVIDUAL WORDS AND FORMULAIC SEQUENCES TAP INTO THE SAME TRAIT: THE PERSPECTIVE OF ASSESSMENT AND THE CONTRIBUTIONS OF PHONOLOGICAL SHORT-TERM MEMORY AND EXPOSURE

Abstract

Nativelike language use is characterized by a high level of formulaicity (Pawley & Syder, 1983; Sinclair, 1991), and formulaic sequences are often believed to be building blocks of language acquisition (Christiansen & Arnon, 2017) and crucial to language fluency (Saito, 2020). Although they consist of multiple words and are analyzable, some researchers argued that the knowledge of formulaic sequences is largely lexical in nature, i.e., stored and processed holistically without recourse to analysis (Wray, 2002). Wray (2008) further proposed a heteromorphic view of mental lexicon, pushing the boundary of vocabulary to encompass not only individual words but also larger-than-word units such as formulaic sequences. The main purpose of the present study was to empirically test this proposal from the perspective of assessment, i.e., see if measures of formulaic sequences tap into the same latent construct underlying measures of individual words. In addition, the present study also investigated the contributions of phonological short-term memory (PSTM) and exposure to the knowledge of formulaic sequences and individual words. The study was carried out in an English as a Foreign Language (EFL) context, and 136 Chinese participants of intermediate to advanced proficiency completed a battery of nine linguistic measures assessing their receptive and controlled productive knowledge of collocations, phrasal verbs, and individual words. In addition, their capacity of PSTM was measured by a non-word span test, and their engagement in various types of English-medium activities was measured by an exposure questionnaire. Confirmatory factor analysis and model comparisons were conducted to examine the factor structure of nine linguistic measures, and a bi-factor solution with a single latent trait factor underlying all nine linguistic measures and a method-specific grouping factor for all six receptive measures was selected as the best-fitting model in terms of fit and parsimony. In addition, structural equation modeling revealed that PSTM, exposure, and length of learning English were all significant predictors for the knowledge of formulaic sequences and the knowledge of individual words. The three predictors combined explained about 33.4% of variance in the knowledge of formulaic sequences and 30.9% of the variance in the knowledge of individual words. However, the contributions of PSTM and exposure to the knowledge of formulaic sequences and to the knowledge of individual words were not significantly different in magnitude. The results provided psychometric evidence supporting the legitimacy of conceptualizing a heteromorphic mental lexicon showing that measures of formulaic sequences and individual words tapped into the same latent trait.