The standard orthography of Northern Sami 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.