Frequency Effects in Morphologisation of Korean /n/-Epenthesis Ogyoung Lee & Vsevolod Kapatsinski University of Oregon ABSTRACT This study accounts for Korean /n/-epenthesis from a usage-based perspective, by describing the reduced productivity of epenthesis as an analogical change in progress. We found that epenthesis probability rises as whole-word frequency increases, supporting the hypothesis that analogical change begins in low- frequency words (Bybee 2002). We interpret the findings as support for the idea that frequent forms are stored and retrieved in production directly while rare words may be derived using grammar. The results further support the existence of morphological strata in Korean. We show that the constituents undergoing /n/- epenthesis are largely limited to native rather than Sino-Korean morphemes. However, not all native morphemes are able to trigger /n/ epenthesis. We argue that particular native morphemes are associated with, and able to trigger, epenthesis to the extent that they tend to occur in epenthesis-favoring contexts (Bybee 2002, Raymond & Brown 2012). Keywords: frequency effects, productivity, lexicalisation, lexical diffusion, whole-word retrieval, computation, strata, sound change 1 Introduction Language is not static but constantly in the process of change. According to usage-based linguistics, the grammar acquired by a language user emerges out of generalisation over experienced utterances. Phonological and morphological schemas, rules, and constraints, the elements of phonological grammar, emerge from generalisation over words. Usage-based linguistics assigns a major role in this process to frequency of use (Bybee 2001: 57). Generalisations supported by many words (i.e. ones of high type frequency) are, other things being equal, more productive (Bybee 1995, 2001). At the same time generalisations exemplified by frequent words (words of high token frequency) tend to be less productive (Bybee & Brewer 1980, Hay 2001, 2003). The basic reason is that frequent words are likely to be accessed whole, rather than through the parts (Alegre & Gordon 1999, Hay 2001, 2003, Hay & Baayen 2001, Kapatsinski 2010a, Kapatsinski & Radicke 2009, Tremblay & Baayen 2010). Therefore the listener is unlikely to parse grammatical patterns out of frequent words in perception, making patterns exemplified by frequent words less salient, and the speaker is unlikely to practice grammatical patterns when producing frequent words. When a pattern loses productivity and is replaced by a competitor (what Bybee, 2001, calls ‘analogical change’), the few words that exceptionally continue to obey the old pattern tend to be of high frequency. For example, as Old English vowel-changing past tense schemas were replaced by -ed, a few frequent verbs, now known as irregular verbs, resisted. Thus, break-broke but stake-staked. The reason again is that the past tense forms of frequent verbs could be directly retrieved from the lexicon without the need to use now unproductive vowel change schemas they seem to support. In this paper, we document that a Korean grammatical pattern, called /n/-epenthesis, has morphologised and is now obeyed only in front of one of three ‘special’ morphemes. Following