Abstract. This article examines the acoustic characteristics of Korean fricatives (lax /s/ and tense /s*/) in three vowel contexts (/a/, /i/, and /u/) in the speech of AE learners of Korean. AE learners fall into two groups based on their proficiency. Acoustically, Korean /s*/
is more similar to English /s/ than the latter is to Korean /s/. In terms of A/F duration ratio, the more similar sound (Korean /s*/) was easier for AE advanced learners of Korean to produce, while in terms of amplitude difference AE learners did not distinguish the Korean fricatives at all
regardless of their proficiency level. In terms of the mean A/F duration ratio, the Korean /s*/ was authentically produced by AE advanced learners, but AE advanced and beginning learners of Korean inaccurately produced Korean /s/ was L2 advanced learners and L1 speakers used different strategies
in the production of Korean fricatives. AE KSL advanced learners showed primacy of duration over amplitude, while AE KSL beginning learners showed no significant acoustic cue effects in differentiating the Korean fricatives /s/ and /s*/ in production. As in the speech production of Korean
fricatives /s/ and /s*/ by AE learners of Korean, factors other than years spent learning L2 should be considered to explain the acquisition of L2 sounds.