Jeju also has consonant allophones that appear only at morpheme boundaries. Some of these are found in Standard Korean, such as the insertion of before or at most word-internal morpheme boundaries; the palatalization of to before an affixal ; and the tensing of obstruents following certain morpheme-final nasals. Other rules are absent in Standard Korean. For instance, a sonorant-final word or morpheme can trigger aspiration (for older speakers) or tensing (for younger speakers) in a subsequent lax consonant. In some cases this is due to an underlying consonant cluster, but not all cases can be explained in this way. Other Jeju-specific processes include the doubling of a word-final consonant when followed by a vowel, glide, or , and the lenition of to at some word boundaries.