Variation of the word-initial liquid in North and South Korean dialects under contact

•North and South Korean word-initial liquid is realized as seven different allophones.•[l] and [ɹ] appear more frequently in South Korean.•[r] and obstruents appear more frequently in North Korean.•Age effects by the L2 contact are found in both dialects.•The effect of dialect contact is partially observed in North Koreans’ speech. This study examines the phonetic variation of the word-initial liquid in two dialects of Korean, Northern Hamkyeong Korean of North Korea and Seoul Korean of South Korea. The goals of the study are two-fold: to provide a thorough description of the phonetic variation in the word-initial liquid in these two dialects and to examine the acquisition of Seoul Korean features by North Koreans residing in Seoul. The participants were prompted to produce initial liquids by reading a list of Sino-Korean words in North Korean orthography and loanwords that begin with a liquid. We found that in addition to tap, the presumed default variant in word-initial position, a variety of variants (nasal, lateral, approximant, obstruent, and trill) are attested in both North and South Korean speakers’ speech, but the proportion of the variants differ by dialect; Northern Hamkyeong speakers produced more obstruent and trill variants than Seoul Korean speakers, while Seoul Korean speakers produced more lateral and approximant variants. We also found evidence for dialect-internal changes and dialect acquisition. The younger Seoul Korean speakers realized the word-initial liquid as lateral more than older speakers, and the use of trill is declining in the North Korean dialect with younger speakers using it less than older speakers. The North Korean speakers who have been in South Korea longer and have the most contact with South Korean speakers tend to produce fewer obstruents.