External photoglottography, intra-oral air pressure, airflow and acoustic data on the Korean fricatives /s’, s/

From simultaneous recordings of the external photoglottography, intra-oral air pressure (P io ), airflow and acoustic data from four native Seoul Korean speakers (2 male and 2 female), we have found that the two fricatives are not significantly different in glottal opening peak and airflow peak height either word-initially or word-medially and that the duration of aspiration is significantly reduced in word-medial /s/, compared to those in word-initial /s/, not in /s’/. We have also found that the duration of a high P io plateau is significantly longer in /s/ than in /s’/ both word-initially and word-medially and that airflow resistance (R=P io /U) at the onset and offset of a P io plateau and at the time of airflow peak height is significantly higher in /s’/ than in /s/ across the contexts. However, the differences in P io peak and F0 are not significant. In addition, the transition time to reach airflow peak height from the offset of a P io plateau is found to be significantly longer in /s/ than /s’/ in both word-initial and word-medial positions. No significant differences in glottal opening peak and airflow peak height confirm that /s/ is specified as [ – spread glottis] like /s’/. As for the other significant differences, we propose that /s/ is [ – tense], and /s’/ [+tense].