not the diphthong ) in the adjacent syllables, it becomes . Before a front vowel in the next syllable, it becomes , e.g. muorji , phonetically . Otherwise, it becomes , e.g. silba , phonetically . This does not occur if the second consonant is a dental/alveolar stop, e.g. gielda , phonetically , or sálti , phonetically . Vowels Northern Sámi possesses the following vowels: Closing diphthongs such as ái also exist, but these are phonologically composed of a vowel plus one of the semivowels or . The semivowels still behave as consonants in clusters. Not all of these vowel phonemes are equally prevalent; some occur generally while others occur only in specific contexts as the result of sound changes. The following rules apply for stressed syllables: Short , , and , the normal diphthongs, and the long vowel occur generally. The other long vowels occur only in the context of diphthong simplification (below). Short is rare, and mostly occurs due to the combination of diphthong simplification plus stressed vowel shortening. Rising diphthongs and half-long occur only due to unstressed vowel shortening in the next syllable. The distribution in post-stressed syllables (unstressed syllables following a stressed one) is more restricted: Short and long , and occur generally. Short and occur more rarely, sometimes from Proto-Samic *i and *u and sometimes as a result of unstressed vowel shortening. Short and occur only before . No diphthongs occur at all, nor do half-long or long and . In a second unstressed syllable (one that follows another unstressed syllable), no long vowels occur and and are the only vowels that occur frequently. The standard orthography of Northern Sámi distinguishes vowel length in the case of versus , although this is primarily on an etymological basis. Not all instances of are phonemically long, due to both stressed and unstressed vowel shortening. Some dialects also have lengthening of under certain circumstances. Nonetheless, a default length can be assumed for these two letters. For the remaining vowels, vowel length is not indicated in the standard orthography. In reference works, macrons can be placed above long vowels that occur in a position where they can be short. Length of and in a post-stressed syllable is assumed, and not indicated, except in the combinations and , where these letters can also indicate short vowels. Dialectal variation The Eastern Finnmark dialects possess additional contrasts that other dialects of Northern