The relationships among L2 fluency, intelligibility, comprehensibility, and accentedness

Fluency, intelligibility, comprehensibility, and accentedness are important dimensions of second language (L2) pronunciation proficiency representing global, listener-based intuitions. This study meta-analyzed 49 reports from 1995 to 2023, examining 141 effect sizes (Pearson r ) to understand their relationships and possible moderators. Three-level meta-analysis models showed weighted mean correlations of .82, .75, .62, .57, and .32 for fluency/comprehensibility, comprehensibility/accentedness, fluency/accentedness, intelligibility/comprehensibility, and intelligibility/accentedness, respectively. Task types moderated correlations for fluency/accentedness, intelligibility/comprehensibility, and intelligibility/accentedness, with controlled tasks leading to higher correlations. Ratings of multiple dimensions by the same listeners tended to result in weaker correlations for fluency/comprehensibility and comprehensibility/accentedness. The findings imply that having an accent does not mean being unintelligible and support prioritizing intelligible and comprehensible speech over accent reduction. The study also highlights an over-reliance on first language speaker norms in L2 pronunciation research and advocates for more transparent reporting.