Exploring the Role of Vocabulary in EFL Learners’ Speaking Proficiency: A Mixed Methods Study

Vocabulary occupies an essential place in speaking. Previous research has examined the vocabulary–speaking link by exploring lexical features and characteristics in spoken discourses, investigating the relationship between vocabulary knowledge and oral proficiency, and inspecting the association between lexical richness and speaking. However, little attempt has been made to integrate these approaches. This three-phase mixed-methods research aimed to resolve the complexities regarding the relationship between vocabulary and speaking in the context of tertiary-level English as a Foreign Language (EFL) learners in China from macro, meso and micro levels. At the macro level, Phase I aimed to quantitatively probe into EFL learners’ vocabulary repertoires and speaking proficiency, particularly to explore the contribution of EFL learners’ receptive, productive and aural vocabulary knowledge to their speaking proficiency. To achieve this aim, a total of 74 elementary to upper-intermediate tertiary-level students were invited to complete three vocabulary tests and one speaking task designed to measure three aspects of vocabulary knowledge (receptive, productive and aural) and speaking proficiency, respectively. Findings showed that all three aspects of vocabulary knowledge were significantly correlated with speaking proficiency and aural vocabulary knowledge made a significant, unique contribution to learners’ oral performance. At the meso level, Phase II examined the lexical dimension of learners’ performance in the speaking task. First, data were quantitatively analysed regarding lexical richness (lexical density, diversity and sophistication) and its relationship to speaking proficiency. Second, 74 students were categorised into four groups according to their speaking scores for the task (elementary, pre-intermediate, intermediate and upper-intermediate). The vocabulary use of each group was qualitatively inspected in terms of lexical features (lexical appropriateness, accuracy and formulaic language). The results indicated that lexical diversity and sophistication were significantly associated with learners’ overall speaking proficiency, indicating that the more proficiently learners speak, the more diverse and sophisticated vocabulary they produce. Multi-group qualitative analyses further revealed different features and patterns of lexical use across various proficiency levels. Phase III drew on stimulated verbal recalls to qualitatively inspect micro-level information regarding vocabulary-related cognition and strategies in the speaking process of a sub-cohort of seven students of varied proficiency. This was done in conjunction with raters’ decisionmaking processes pertaining to lexis in assessing these seven students. These students were randomly selected from the four groups in Phase II. Students’ and raters’ views on vocabulary and speaking were also collected via semi-structured interviews. The findings from the qualitative analysis revealed that learners paid more attention to lexical diversity, sophistication and fluency in their speaking. In contrast, raters assigned greater importance to lexical appropriateness, accuracy and fluency in assessing lexis in speaking. These findings help clarify the myth among Chinese EFL learners — blaming ‘far-fromsatisfactory speaking’ for ‘never enough vocabulary’. They also provide insightful implications for teaching, learning and assessing vocabulary in speaking.

Name thesis:degree_name

PhD

Level thesis:degree_level

Doctoral

Discipline thesis:degree_discipline

Applied Linguistics

Grantor dc:publisher

ResearchSpace@Auckland

Year dc:date.issued

2023

Author dc:creator

• Guo, Junyan

Advisors dc:contributor.advisor

• East, Martin
• Wang, Danping

Statement dc:rights

• Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated.

Licence dc:rights.uri

• https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm

Handle dc:identifier.uri

https://hdl.handle.net/2292/64622

OAI identifier oai:identifier

oai:researchspace.auckland.ac.nz:2292/64622