most languages have differences in length of vowels or consonants, but in the case of most languages it would not be treated phonemically or phonologically as distinctive or contrastive. even in those languages which do have phonologically contrastive length, a chroneme is only posited in particular languages. use of a chroneme views as being composed of two segments: and , whereas in a particular analysis, may be considered a single segment with length one of its features. this may be compared to the analysis of a diphthong like as a single segment or as the sequence of a vowel and consonant: .