This paper puts forward the description, classification and phonemic analysis of the vowels and diphthongs of a variety of the 'standard' dialect of Maithili. It also includes brief discussions on the vowel clusters in Maithili. The main conclusions are summarised at the end of the paper.
Vowels can be defined in terms of both phonetics and phonology. Phonetically, they are sounds articulated without a complete closure in the mouth or degree of narrowing which would produce audible frication; the air escapes evenly over the centre of the tongue. If the air escapes solely through the mouth, the vowels are said to be oral. If on the other hand, some air is simultaneously released through the nose, the vowels are said to be nasal. From a phonological point of view, vowels are those units which function as the focus of vowels.