The efficacy of lexical stress diacritics on the English comprehensibility and accentedness of Korean speakers

The purpose of the study was to examine the efficacy of lexical stress diacritics on the English comprehensibility and accentedness of Korean speakers. To this end, 30 native Korean participants read aloud 15 English sentences without diacritics in the pretest. Then, they were given explicit instructions on the production of higher pitch and extended duration as a marker of English stress with musical notation provided. In the posttest, the participants read aloud the same sentences as were in the pretest but which had diacritics indicating stress placement. In the delayed posttest, two days after the pretest and the posttest, the participants read 15 sentences without diacritics again to see if the effects of the treatment were retained. Randomized speech samples were rated by three native speakers of English in relation to comprehensibility and accentedness. Findings showed that significant improvements were observed after the treatment in both comprehensibility and accentedness.