Acoustic and perceptual asymmetries in Korean /o/ and /u/: A study on cue weighting and gender differences

The Korean phonemes /o/ and /u/ are reported to be undergoing an ongoing merger in the F1 and F2 acoustic space, particularly among female speakers. This study investigates how cue weighting shifts during this sound change in both production and perception, and whether male speakers demonstrate better perception of these phonemes due to their less overlapped F1, F2 space compared to female speakers. A perception experiment was conducted following confirming the distribution of production cues (F1, F2, H1-H2, H1-A1). Production results from five female and five male speakers indicate that males produce the two phonemes more distinctively than females. Among female speakers, only F2 plays a significantly strong role in distinguishing /o/ and /u/, while for male speakers, F1, F2, and H1-A1 are all critical for differentiating the two phonemes. However, the perception results reveal a less pronounced gender difference compared to production, with female speakers even outperforming males, contrary to the production findings. This suggests a discrepancy between gender differences in acoustic production and perceptual abilities. Additionally, F2 emerged as the most prominent cue for both the production and perception of /o/ and /u/.