This study examined the componential structure of second-language (L2) speaking profi ciency. Participants-181 L2 and 54 native speakers of Dutch-performed eight speaking tasks and six tasks tapping nine linguistic skills. Performance in the speaking tasks was rated on functional adequacy by a panel of judges and formed the dependent variable in subsequent analyses (structural equation modeling). The following independent variables were assessed separately: linguistic knowledge in two tests (vocabulary and grammar); linguistic processing skills (four reaction time measures obtained in three tasks: picture naming, delayed picture naming, and sentence building); and pronunciation skills (speech sounds, word stress, and intonation). All linguistic skills, with the exception of two articulation measures in the delayed picture naming task, were signifi cantly and substantially related to functional adequacy of speaking, explaining 76% of the variance. This provides substantial evidence for a componential view of L2 speaking profi ciency that consists of languageknowledge and language-processing components. The componential structure of speaking profi ciency was almost identical for the 40% of participants at the lower and the 40% of participants at the higher end of the functional adequacy distribution ( n = 73 each), which does not support Higgs and Clifford's ( 1982 ) relative contribution model, predicting that, although L2 learners become more profi cient over time, the relative weight of component skills may change.Adult native (L1) speakers differ with respect to communicative success when they speak. Some speak slowly, others fast; some articulate poorly, others well; the speech of some is characterized by a high incidence of short utterances, false starts, and self corrections, and the speech of others is characterized by long and fl awless utterances (Levelt, 1989 ). Such differences are also likely to show up in the speech of second language (L2) speakers. Compared to L1 speakers, however, L2 speakers encounter more problems in fi nding the right words, in giving their utterances the correct morphosyntactic form, and in articulating their utterances correctly and fl uently (Kormos, 2006 ;Poulisse, 1999 ). This study aims to explore the componential structure of speaking profi ciency of L2 learners at intermediate and advanced levels of L2 proficiency. In other words, this study is concerned with a fundamental issue, which has to be addressed prior to any practical matters, such as the assessment of L2 learners' profi ciency (Schoonen, 2011 ). Previous research on the components of L2 speaking profi ciency and the rationale of the current study is presented in the next two sections.
Previous Research Investigating Components of L2 Speaking Profi ciencyThere have been several studies that aimed to unravel the componential structure of L2 speaking profi ciency. Two general approaches can broadly be distinguished, labeled here as the subjective-subjective and the subjective-objective approach. In the subjective...