Tensification as a general marker of compound boundary in Korean

Compound tensification (CT) in Korean refers to the process where an underlyingly plain obstruent surfaces as tense at the onset of the second noun in a noun + noun compound, traditionally attributed to a historical genitive marker. Thus, CT is known to only affect subordinate compounds, where the first noun modifies the second noun. However, this study tests whether CT generalizes to coordinate compounds, where the two nouns form a conjunctive relation. In a production experiment with 33 native Seoul Korean speakers, tokens containing plain stops at compound boundaries were elicited and perceptually categorized. Results show that while CT occurred more frequently in subordinate compounds, it also emerged in coordinate compounds, especially in shorter, high-frequency words like pom-kaul (‘spring and fall’). Acoustic analysis confirmed that stops perceived as tense exhibited significantly longer closure durations across both compound types. These findings suggest an expansion of CT beyond its historically constrained environment.