In second language (L2) research and in some types of L2 testing, measures of complexity, accuracy and fluency (CAF) are widely applied both to capture performance of language learners as well as...Show moreIn second language (L2) research and in some types of L2 testing, measures of complexity, accuracy and fluency (CAF) are widely applied both to capture performance of language learners as well as to assess L2 learners’ proficiency underlying their performance. In spite of the long research interest in CAF, many questions are still raised, including a significant question as to what extent L2 CAF measures are correct indicators of L2 proficiency. A speaking-oriented study by De Jong et al. (2015) indicates that measures of L1 and L2 fluency are strongly correlated and therefore concluded that there was a large overlap for many aspect of fluency. This study aimed to examine L2 complexity, accuracy and fluency measures and compared them to L1 behavior. Furthermore, the current study also considered whether such correlations are stronger for high-proficient L2 Speakers. Spontaneous speech of 10 native speakers of Armenian and 19 native speakers of Arabic with L2 Dutch is recorded and analyzed with regard to complexity, accuracy, and fluency. Analysis revealed that measures of Complexity, accuracy, and fluency (CAF) in L1 do not significantly correlate with the equivalent measures in L2. The findings would support the threshold hypothesis (LTH), indicating that some threshold of proficiency needs to be attained in L2 before L1 skills can be transferred in the L2.Show less