The purpose of this article is to define the present system of vowels in standard Meadow Mari based on empirical research and in the light of traditional concepts. The specific objectives of this experiment were (1) to ascertain whether three often-called weak full vowels can be described as such or whether they are better described as reduced vowels, (2) to determine the quality of the central vowel, and (3) to measure the extent of roundedness of all vowels. The paper includes a brief consideration of personal features that may be apparent from analyses of formants 3 and 4. Four perspectives were considered: (a) the positions of the vowels on a chart displaying formants 1 and 2, (b) duration, (c) fundamental frequency and (d) intensity. The method used is statistical analysis of acoustic measurements using a speech analysis computer program. The findings suggest that there are only two vowel categories in Meadow Mari, full and reduced, as opposed to views which add a third category, weak. The central vowel is reduced and is neutral with regard to rounded.