How inaccurate rhymes reveal Old Norse vowel phonemes

This article discusses so-called inaccurate rhymes in Old Norse dróttkvætt poetry and their bearing on the phoneme structure of Old Norse. Inaccurate rhymes between /ǫ/ and /a/ do occur, but were to some extent avoided in Old Norse poems in the eleventh and the twelfth century. The same applies to rhymes between /ǫ́/ and /á/ in the second half of the twelfth century. This avoidance confirms the status of /ǫ́/ as a phoneme by providing, indirectly, an opposition between /á/ and /ǫ́/. Furthermore, rhymes between the diphthong /ja/ and the vowel /a/ were used infrequently in the tenth century, and the diphthong /jó/ and the vowel /ó/ were not rhymed at all. Thus /ja/ and /jó/ were not treated as a sequence of a consonant /j/ and a vowel.