Measures of second language (L2) learners’ vocabulary size have been shown to correlate with language proficiency in reading, writing and listening skills, and vocabulary tests are sometimes used for placement purposes. However, the relation between learners’ vocabulary knowledge and their speaking skills has been less thoroughly investigated, and even less so in terms of pronunciation. In this article, we compare vocabulary and pronunciation measures for 25 Italian instructed learners of L2 French. We measure their receptive (Dialang score) and productive (vocd-D, MTLD) vocabulary size, and calculate the following pronunciation indices: acoustic distance and overlap of realizations for selected L2 French vowel pairs, ratings of nasality for ratings of foreign-accentedness, fluency metrics. We find that vocabulary measures show low to medium correlations with fluency metrics and ratings of foreign-accentedness, but not with vowel metrics. We then turn our attention to the impact of research methods on the study of vocabulary and pronunciation. More specifically, we discuss the possibility that these results are due to pitfalls in vocabulary and pronunciation indices, such as the failure of Dialang to take into account the effect of L1-L2 cognates, and the lack of measures for evaluating consonants, intonation and perception skills.