IN representing the vowels of the Isaaq dialect of Somali 2 we meet with many difficulties not only because of a large number of vowel distinctions but also on account of the operation of Vowel Harmony. I use the term Vowel Harmony in the same sense as Armstrong, 3 i.e. as the harmony (or ‘matching’) of vowels belonging to the same series. Schleicher, 4 Reinisch, 5 and Abraham 6 use this term quite differently, meaning by it certain types of assimilation of vowels without postulating two vowel series. Armstrong was the first writer in the literature on Somali to become aware of the existence and complexity of the problems under discussion.