|Sound change and alternation|
In phonology, syncope ( //; from Ancient Greek: συγκοπή, translit. sunkopḗ, lit. 'cutting up') is the loss of one or more sounds from the interior of a word, especially the loss of an unstressed vowel. It is found both in synchronic analysis of languages and diachronics. Its opposite, whereby sounds are added, is epenthesis.
- In some verbs
- imir (to play) should become *imirím (I play). However, the addition of the -ím causes syncope and the second-last syllable vowel i is lost so imirim becomes imrím.
- In some nouns
- inis (island) should become *inise in the genitive case. However, instead of *Baile na hInise, road signs say, Baile na hInse (the town of the island). Once again, there is the loss of the second i.
If the present root form in Irish is the result of diachronic syncope, there is a resistance to synchronic syncope for inflection.
Sounds may be removed from the interior of a word as a rhetorical or poetic device: for embellishment or for the sake of the meter.
- Latin commōverat > poetic commōrat ("he had moved")
- English hastening > poetic hast'ning
- English heaven > poetic heav'n
- English over > poetic o'er
- English ever > poetic e'er, often confused with ere ("before")
Various sorts of colloquial reductions might be called "syncope" or "compression". 
Forms such as "didn't" that are written with an apostrophe are, however, generally called contractions:
- English Australian > colloquial Strine, pronounced //
- English did not > didn't, pronounced //
- English I would have > I'd've, pronounced //
- English going to > colloquial gonna (generally only when unstressed and when expressing intention rather than direction), pronounced // or, before a vowel, //
In historical phonology, the term "syncope" is often limited to the loss of an unstressed vowel, in effect collapsing the syllable that contained it: trisyllabic Latin calidus (stress on first syllable) develops as bisyllabic caldo in several Romance languages.
- Old English hlāfweard > hlāford > Middle English loverd > Modern English lord, pronounced //
- English Worcester, pronounced //
- English Gloucester, pronounced //
- English Leicester, pronounced //
- English Towcester, pronounced //
- Latin cálidum > Italian caldo [ˈkaldo] "hot"
- Latin óculum > Italian occhio [ˈɔkkjo] "eye"
- Latin tremuláre > Italian tremare [treˈmaːre] "to tremble"
- Proto-Norse armaʀ > Old Norse armr "arm"
- Proto-Norse bókiʀ > Old Norse bǿkr "books"
- Proto-Germanic *himinōz > Old Norse himnar "heavens"
A syncope rule has been identified in Tonkawa, an extinct American Indian language in which the second vowel of a word was deleted unless it was adjacent to a consonant cluster or a final consonant. 
- Apheresis (linguistics)
- Clipping (morphology)
- Clipping (phonetics)
- Deletion (phonology)
- Epenthesis, the addition of sounds to the interior of a word
- Relaxed pronunciation
- Syncopation in music
- Vowel reduction
- by the Rev.