The Effects of Lexical Competition on Hyperarticulation of Voice Onset Time and Fundamental Frequency in Korean Stops: Experimental and Big Data Approaches

Abstract

The ongoing tonogenetic sound change in Seoul Korean involves transphonologization in phrase initial position, where the fundamental frequency (F0) of the vowel following aspirated or lenis stops becomes associated with the aspirated-lenis stop contrast (phonologization), while the originally contrastive Voice Onset Time (VOT) values merge (dephonologization). One critical aspect that remains unexplored in this context is the impact of lexical competition, often evaluated through minimal pairs. This dissertation explores the influence of lexical competition on hyperarticulation in Korean stops within this ongoing tonogenetic sound change. It aims to investigate how hyperarticulation influences sound change and how speakers adapt to the change. The study conducted production experiments on both phrase-initial and phrase-medial stops, alongside analyzing a large dialogue corpus dataset. The statistical analyses of experimental data reveal that speakers hyperarticulate the VOT of aspirated stops, resulting in a greater VOT contrast, and tend to hyperarticulate the F0 of lenis stops, leading to a greater F0 contrast when they have a lenis minimal pair. Similarly, corpus analyses indicate hyperarticulation of VOT and F0 in aspirated stops, resulting in an expanded contrast for both of these cues as well. These findings suggest two main points: 1) the hyperarticulation effect observed in the current dissertation is `context-free' contrastive hyperarticulation, suggesting that this process is related to speaker-internal processes, and 2) the presence of a minimal pair inhibits VOT merger due to its continuing high functional load in the speech community. In phrase medial position, the aspirated-lenis contrast is not reported to involve any F0 contrast. However, statistical results of experimental data on phrase-medial stops show that speakers who rely more on F0 for distinguishing phrase-initial aspirated and lenis stops also now use F0 for distinguishing phrase-medial aspirated and lenis stops. These observations suggest an emerging tonogenetic sound change extending the F0 contrast to the phrase-medial position, marking genuine tonogenesis.