Length
While vowels bearing phonemic length are normally known as simply long vowels, a more common term for consonants is geminate consonant.
Transcription
Length marks
In the IPA, a special length mark /ː/ is used following a segment to mark that it is long. Most ASCII renditions of the IPA substitute the colon: /:/.
Diacritics
In the Latin alphabet, the oldest mark of length may be the acute. It is still used in this function in e.g. Czech and Hungarian.
A widely spread practice of marking length in work on linguistics, particularly on vowels (but occasionally also on consonants) is the use of the macron. In day-to-day orthographies this is found in Latvian and has also been adopted for e.g. Māori.
In Lithuanian the ogonek is used to mark long vowels (originally long nasal vowels in particular).
Digraphs
The most common digraph convention for writing length is to write the corresponding single segment twice: this is used e.g. in Finnish for both consonants and vowels (maassa /mɑːsːɑ/). There are however exceptions: e.g. in oldest Greek, long /eː oː/ were written as if they were /ei/ and /ou/, i.e. as ‹ει ου›.
English features an abundance of non-trivial vowel digraphs for marking its long vowels. A particularly interesting convention is the magic e, a set of non-contiguous vowel digraphs marking length (as well as certain diphthongs). E.g. the digraph u…e in plume marks /uː/, contrasting with plain u in plum marking the entirely different vowel /ʌ/.
Dedicated letters
The Greek alphabet contains two vowel letters that originally signified certain long vowels in particular:
- eta ‹Η η›, marking originally a long open front vowel /æː~ɛː/ but later rising to close /eː/
- omega ‹Ω ω›, marking originally a long open back vowel /ɔː/
These were originally unpaired long vowels, but later in Koine Greek these contrasted with epsilon ‹Ε ε› and omicron ‹Ο ο› for the corresponding short vowels. In modern Greek these are
Lithuanian uses the letter ‹y› as an alternate to ‹į› for representing /iː/.
Typology of length
Long versus short phonemes
A common phenomenon is the occurrence of long vowels that have no short counterparts. This frequently results from e.g. the smoothing of former diphthongs. E.g. classical Arabic has three short vowels /a i u/ and three long vowels /aː iː uː/, as well as two diphthongs /ai au/. In several modern Arabic varieties the latter two have smoothed to /eː oː/, which have no corresponding short vowels.
By contrast, the occurrence of geminate consonants almost always implies the existence of the corresponding short consonants. One known near-counterexample is older Finnish, where /ŋ/ appears only in the consonant cluster /ŋk/ and as the geminate /ŋŋ/. (In modern standard Finnish, /ŋ/ can occur in various other positions due to the introduction of loanwords such as anglismi /ɑŋlismi/.)
