how many vowels does it have?
Old Norse had nasalized versions of all ten vowel places.
Old Norse
Old Norse had nasalized versions of all ten vowel places. These occurred as allophones of the vowels before nasal consonants and in places where a nasal had followed it in an older form of the word, before it was absorbed into a neighboring sound. If the nasal was absorbed by a stressed vowel, it would also lengthen the vowel. These nasalizations also occurred in the other Germanic languages, but were not retained long. They were noted in the First Grammatical Treatise, and otherwise might have remained unknown. The First Grammarian marked these with a dot above the letter. This notation did not catch on, and would soon be obsolete. Nasal and oral vowels probably merged around the 11th century in most of Old East Norse. However, the distinction still holds in Dalecarlian dialects. The dots in the following vowel table separate the oral from nasal phonemes.

Note: The open or open-mid vowels may be transcribed differently:
what is the scientific classification of a butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the order Lepidoptera, which also includes moths. from where did it get its name? It derives from the Old English "butorflēoge" what kind of language is the above mentioned one? It is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. did any other languages influence it? Latin, Old Norse how is the latter related to english? Old English and Old Norse were related languages. It is therefore not surprising that many words in Old Norse look familiar to English speakers. This is because both English and Old Norse stem from a Proto-Germanic mother language
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Old Norse [SEP] Vowels
The vowel phonemes mostly come in pairs of long and short. The standardized orthography marks the long vowels with an acute accent. In medieval manuscripts, it is often unmarked but sometimes marked with an accent or through gemination. Old Norse had nasalized versions of all ten vowel places. These occurred as allophones of the vowels before nasal consonants and in places where a nasal had followed it in an older form of the word, before it was absorbed into a neighboring sound. If the nasal was absorbed by a stressed vowel, it would also lengthen the vowel. These nasalizations also occurred in the other Germanic languages, but were not retained long.