Gemination  In phonetics and phonology, gemination (), or consonant lengthening, is an articulation of a consonant for a longer period of time than that of a single instance of the same type of consonant. It is distinct from stress. "Gemination" literally means "twinning" and comes from the same Latin root as "Gemini". Consonant length is a distinctive feature in certain languages, such as Arabic, Berber, Maltese, Catalan, Danish, Estonian, Finnish, Classical Hebrew, Hindi, Hungarian, Italian, Japanese, Latin, Malayalam, Marathi, Persian, Polish, Punjabi, Tamil, Telugu and Urdu. Other languages, such as the English language, do not have phonemic consonant geminates. Vowel length is distinctive in more languages than consonant length. Consonant gemination and vowel length are two different phenomena in languages like Arabic, Japanese, Finnish and Estonian; however, in languages like Italian, Norwegian and Swedish, vowel length and consonant length are interdependent. For Norwegian and Swedish, at least, gemination of a consonant requires a short vowel in the syllable before it, while ungeminated consonants produce a long vowell in the syllable before it. A clear example are the Norwegian words "tak" ("ceiling or roof" of a building, pronouced with a long /ɑː/), and "takk" ("thanks", pronounced with a short /ɑ/. Lengthened fricatives, nasals, laterals, approximants and trills are simply prolonged. In lengthened stops, the obstruction of the airway is prolonged, which delays release, and the "hold" is lengthened. In terms of consonant duration, Berber and Finnish are reported to have a 3 to 1 ratio, compared with around 2 to 1 (or lower) in Japanese, Italian, and Turkish. Gemination of consonants is distinctive in some languages and then is subject to various phonological constraints that depend on the language. In some languages, like Italian, Swedish, Faroese, Icelandic, and Luganda, consonant length and vowel length depend on each other. A short vowel within a stressed syllable almost always precedes a long consonant or a consonant cluster, and a long vowel must be followed by a short consonant. In Classical Arabic, a long vowel was lengthened even more before permanently-geminate consonants.