In linguistics, a chroneme is a basic, theoretical unit of sound that can distinguish words by duration only of a vowel or consonant. The noun chroneme is derived , and the suffixed -eme, which is analogous to the -eme in phoneme or morpheme. However, the term does not have wide currency and may be unknown even to phonologists who work on languages claimed to have chronemes. 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 being 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: . For the purposes of analysis of a chronemic contrast, two words with different meaning that are spoken exactly the same except for length of one segment are considered a minimal pair. The International Phonetic Alphabet (IPA) denotes length by doubling the letter or by diacritics above or after the letters: American English does not have minimal pairs indicating the existence of chronemes or may theoretically be said to have only one chroneme. Some other dialects such as Australian English have contrastive vowel length, but it is not analysed as the consequence of a chroneme. Many Indo-European languages, including Classical Latin, have distinctive length in consonants, for example in Italian: Japanese, some Italian dialects, and Thai have distinctive length in vowels. For example, in Thai: See, for example, the cŭ/cū minimal pair in the dialect spoken near Palmi, Calabria (Italy): or a more general example for the Sicilian language as a whole: Almost all Uralic languages, such as Finnish, Hungarian and Estonian have a distinctive moraic chroneme as a phoneme (also arguably called archiphoneme or epenthetic vowel/consonant). The etymology of the vocalic chroneme has been traced to a voiced velar fricative in the hypothetical Proto-Uralic language, such that becomes . For example, taka- "back-", takka "fireplace" and taakka "burden" are unrelated words. It is also grammatically important; the third person marker is a chroneme (menee "s/he goes"), and often in the spoken