Diversity of vowel systems

Abstract

Systems of vowels vary greatly across the world’s languages while nonetheless conforming to certain general structural patterns. All languages have at least two qualitative distinctions between vowels based on the major parameters of height, backness and rounding, but probably none has more than 15 or so, and the modal number is 5. Generally these basic vowel qualities respect dispersion principles, but deviations can be considerable. When additional parameters, such as nasalization, length, phonation type and pharyngealization are included, the total number of vowel distinctions may easily exceed 40. These ‘‘additive’’ features never occur with a larger number of vowel qualities than those occurring in a ‘‘plain’’ series. Languages may differ markedly in the distributional patterns of their vowels as well as in their inventory. Some languages have different (usually reduced) vowel inventories in unstressed or other non-prominent positions; others constrain vowel sequences in (phonological) words through vowel harmony limitations. Co-occurrence patterns between vowels and consonants also vary greatly, as does the degree of coarticulation between vowels and neighboring segments. Learners must master all of these factors to speak an individual language fluently. Constraints that are universal or shared may be expected to facilitate this task.