An Investigation of the Manner Contrast in Inter-vocalic Korean Stops

Korean has nine stop consonants that are all phonemically voiceless. They occur in three different places of articulation, i.e. bilabial, alveolar, and velar. The alveolar stops are also described as alveo-dental since they are produced with the front of the tongue touching the back of the upper teeth. Three different manners of Korean stops have been referred to in various ways by phonetic researchers. Type I, which is produced with a strong puff of air, is described as heavily aspirated or aspirated. Type II, which is produced with little aspiration, is described as slightly aspirated, lax, or lenis. Type III, which is produced with a tight glottal constriction, is described as reinforced, tense, or fortis. We will refer the Korean stops as aspirated, lax, and tense, hereafter. All nine stops occur in word-initial position as voiceless. Since it is rather unusual having all voiceless stops, the word-initial Korean stops have received much attention from phonetic researchers over the past several decades. Those languages with three (or more) different types of manner, such as Thai and Hindi, often have voiced, voiceless unaspirated, and voiceless aspirated stops (Ladefoged & Maddieson, 1996). While both aspirated and tense Korean stops remain as voiceless in inter-vocalic position, the lax Korean stops become voiced inter-vocalically. In word-final position, all three types of Korean stops are neutralized to their homorganic lax stops and they are often unreleased. Bilabial and alveolar tense stops do not occur in word-final position. The present study investigates the acoustic characteristics of the inter-vocalic Korean stops. Phonemically, the inter-vocalic stops can occur either in the coda position of the first syllable followed by the vowel (VC.V) or in the onset position of the second syllable which is preceded by the vowel (V.CV). In either case, the actual utterances have a V.CV structure within the same word via the resyllabification process. The present study provides absolute physical measurements of the inter-vocalic Korean stops to re-examine the previous impressionistic or phonological treatment of the allophonic variations of Korean stops. Even though many acoustic characteristics of inter-vocalic stops can be found both in the stop portion of the utterance and in the neighboring segment due to the coarticulation process, we focus on three acoustic features, Closure duration, Voice Onset Time and Fundamental frequency of the following vowel.