In
phonetics,
gemination happens when a spoken
consonant is pronounced for an audibly longer period of time than a short
consonant.
Consonant length is distinctive in some languages, for instance Italian, Latin, Japanese, Arabic, Finnish, Hungarian and Luganda. Most languages (including English) do not have distinctive long consonants.
Lengthened fricatives, nasals, laterals, approximants, and trills are simply prolonged. In lengthened stops, the "hold" is prolonged. Long consonants are usually around one and a half or two times as long as short consonants, depending on the language. Consonant length is phonemic in Finnish For example, takka ['tak?a] (transcribed with the length sign IPA [?] or with a doubled sign ['takka]), 'fireplace', but taka ['taka], 'back'.
In some languages, e.g. Italian, Swedish and Luganda, consonant length and vowel length depend on each other. That is, a short vowel within a stressed syllable always precedes a long consonant or a consonant cluster, whereas a long vowel must be followed by a short consonant.
