stem-final is lost before a vowel-initial suffix. Similar to Standard Korean, a stem-final diphthongizes a subsequent vowel by inserting the onglide . Unlike in its sister language, Jeju insertion may occur even with an intervening consonant, and between a verb stem ending in , , or and a suffix with initial . Many of Jeju's consonant-initial verbal suffixes take an initial epenthetic vowel if the previous morpheme ends with a consonant. The default epenthetic vowel is , but the vowel surfaces as following a sibilant and as following an underlying labial. Like Standard Korean but unlike Middle Korean, Koreanic vowel harmony is no longer generally applicable in all native morphemes but remains productive in sound symbolism and certain verbal suffixes. Jeju has two harmonic classes, yin and yang. The neutral vowel can occur with either class. For instance, the perfective aspect marker takes the vowel harmonic allomorph after verb stems whose (final) vowel is yang: In certain cases, suffix allomorphs do not match the harmonic class of the previous vowel. Verb stems with final vowel or take the yang allomorph if their Middle Korean forms were , thus conserving their original harmonic class while violating their current one. Disyllabic stems that end in also take the yang allomorph, but monosyllabic stems or disyllabic stems do not. Phonotactics Jeju syllable structure is (C)(G)V(C) with G being a glide. As in Standard Korean, cannot occur syllable-initially, and does not occur word-initially in native words. Prosody Jeju does not have phonemic vowel length, stress, or tone. Its phonological hierarchy is characterized by accentual phrases similar to those of Standard Korean, with a basic Low-High-Low-High tonal pattern varying according to sentence type, but there are also important differences in the two languages' prosody. Jeju has a weaker tonal distinction within the first half of the accentual phrase than Seoul Korean does, while its aspirate consonants do not produce as significant a high pitch as their Seoul equivalents. Jeju uses more contour tones, where the pitch shifts within a single syllable, than Seoul Korean. Unlike in Seoul Korean, older and fluent speakers of Jeju will also lengthen the final vowel of both clauses in alternative questions. Grammar ORD: ordinal numeral INTR: interrogative MED: medial demonstrative SE: sentence ender CE: canonical ending REP : reportive NPST: nonpast Jeju is typologically similar to Korean, both being head-final agglutinative languages. However, the two languages show significant differences in