Perception of English /r/ and /l/ speech contrasts by native Korean listeners with extensive English-language experience

Native speakers of Korean often have difficulty perceiving the English /r/-/l/ sounds. In view of this, we sought to examine the degree to which very extensive exposure to the English language as an adult, through many years of living in a predominantly English-language environment, affects the perception of “difficult” English speech contrasts such as /r/-/l/. This study was therefore designed to study aspects of the speech perception abilities of adults who were native speakers of Korean but who had lived for many years in an English-speaking environment. The ability to distinguish English /r/ vs. /l/ contrasts was measured using a two-alternative forced-choice [r-l] identification task. 12-bit, 10-kHz sampled signals were processed digitally to convert them to the format required for our computer programs. The resulting signals were stored on computer disk as 16-bit, 16-kHz signals in CSRE (Canadian Speech Research Environment) format. This [r-l] test consisted of five minimal pairs (e.g. rock-lock) within each of five phonetic environments: initial singleton, initial consonant cluster, medial, final consonant cluster, and final singleton