In linguistics, an elision or deletion is the omission of one or more sounds (such as a vowel, a consonant, or a whole syllable) in a word or phrase. Sometimes sounds are elided to make a word easier to pronounce. The word elision is frequently used in linguistic description of living languages, and deletion is often used in historical linguistics for a historical sound change.
In English as spoken by native speakers, elisions come naturally, and are often described as "slurred" or "muted" sounds. Often, elisions are deliberate. It is a common misconception that contractions automatically qualify as elided words, which comes from slack definitions: not all elided words are contractions and not all contractions are elided words (for example, 'going to' → 'gonna': an elision that is not a contraction; 'can not' → 'cannot': a contraction that is not an elision).
In French, elisions are mandatory in certain contexts, as in the clause C'est la vie (elided from *Ce est la vie).
In Spanish, elisions occur less frequently but are common in certain dialects. They are never marked by an apostrophe in writing. Of particular interest is the word para, which becomes pa. Multiple words can be elided together, as in pa trabajar for para trabajar and pa delante or even pa lante for para adelante.
Elisions likely occurred regularly in Latin, but were not written, except in inscriptions and comedy. Elision of a vowel before a word starting in a vowel is frequent in poetry, where the metre sometimes requires it. For example, the opening line of Catullus 3 is Lugete, O Veneres Cupidinesque, but would be read as Lugeto Veneres Cupidinesque.
Some morphemes take the form of elision: see disfix.