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.