Second language (L2) learners of English must learn to produce English phonemes, words, and sentences. These L2 learners make many errors when learning English; they may change the place or manner of articulation, insert vowels, or delete consonants. Obstruent sounds, such as fricatives, affricates, and stops, can be especially difficult for L2 learners. This study analyzed native English speakers<'> perception of the quality of obstruents produced by native Mandarin Chinese and Korean speakers. Target words containing obstruents had been produced in three different tasks: in a carrier phrase, in a paragraph, and in a spontaneous speech sample. Obstruents were produced in word-initial position and word-final position. Raters with differing levels of expertise listened to these words and rated the perceptual quality of the obstruents within the words. This study found that overall, English obstruent productions by native Mandarin and Korean L2 speakers learning English were rated most clear when produced in word-initial position in a carrier phrase or a paragraph. The lowest ratings given were of obstruents in word-final position in spontaneous speech. No significant differences were found for listener expertise level. Combined with future research, results from this study will help educate the field of second language instruction as to how the speech of Korean and Mandarin learners of English is perceived. It also provides additional information on the effect that listener expertise has on the judgment of L2 speech production.

Second language (L2) learners of English must learn to produce English phonemes, words, and sentences. These L2 learners make many errors when learning English; they may change the place or manner of articulation, insert vowels, or delete consonants. Obstruent sounds, such as fricatives, affricates, and stops, can be especially difficult for L2 learners. This study analyzed native English speakers’ perception of the quality of obstruents produced by native Mandarin Chinese and Korean speakers. Target words containing obstruents had been produced in three different tasks: in a carrier phrase, in a paragraph, and in a spontaneous speech sample. Obstruents were produced in word-initial position and word-final position. Raters with differing levels of expertise listened to these words and rated the perceptual quality of the obstruents within the words. This study found that overall, English obstruent productions by native Mandarin and Korean L2 speakers learning English were rated most clear when produced in word-initial position in a carrier phrase or a paragraph. The lowest ratings given were of obstruents in word-final position in spontaneous speech. No significant differences were found for listener expertise level. Combined with future research, results from this study will help educate the field of second language instruction as to how the speech of Korean and Mandarin learners of English is perceived. It also provides additional information on the effect that listener expertise has on the judgment of L2 speech production.