Tenseness

In phonology, tenseness or tensing is the pronunciation of a vowel with a relatively longer duration and with the tongue positioned slightly higher and less centralized in the mouth compared with another vowel, thus causing a phonemic contrast between the two vowels. Contrast between vowels on the basis of tenseness is common in many languages, including English; for example, in most English dialects, [iː] (as in the word beet) is the tense counterpart to the lax /ɪ/ (as in bit), and /uː/ (as in kook) is the tense counterpart to the lax /ʊ/ (as in cook). The opposite quality of tenseness, in which a vowel is produced as relatively more shortened, lowered, and centralized, is called laxness or laxing.

Unlike most distinctive features, the feature [tense] can be interpreted only relatively, often with a perception of greater tension or pressure in the mouth, which, in a language like English, contrasts between two corresponding vowel types: a tense vowel and a lax vowel. An example in Vietnamese is the letters ă and â representing lax vowels, and the letters a and ơ representing the corresponding tense vowels. Some languages like Spanish are often considered as having only tense vowels, but since the quality of tenseness is not a phonemic feature in this language, it cannot be applied to describe its vowels in any meaningful way. The term has also occasionally been used to describe contrasts in consonants.