Colloquial Welsh morphology

The morphology of the Welsh language has many characteristics likely to be unfamiliar to speakers of English or continental European languages like French or German, but has much in common with the other modern Insular Celtic languages: Irish, Scottish Gaelic, Manx, Cornish, and Breton. Welsh is a moderately inflected language. Verbs inflect for person, number, tense, and mood, with affirmative, interrogative, and negative conjugations of some verbs. There is no case inflection in Modern Welsh.

Modern Welsh can be written, and spoken, in several levels of formality, for example colloquial or literary, as well as different dialects. The grammar described in this article is for Colloquial Welsh, which is used for speech and informal writing. Literary Welsh is closer to the form of Welsh used in William Morgan's 1588 translation of the Bible and can be seen in formal writing. It does not reflect the spoken language presented here.

Initial consonant mutation is a phenomenon common to all Insular Celtic languages, although there is no evidence of it in the ancient Continental Celtic languages of the first millennium AD; nor was there any evidence of this in the Insular Celtic languages around the 500s.

The first consonant of a word in Welsh may change when preceded by certain words (e.g. i, o, yn, and a), or because of some other grammatical context (such as when the grammatical object follows a conjugated verb). Welsh has three mutations: the soft mutation (Welsh: treiglad meddal), the nasal mutation (Welsh: treiglad trwynol), and the aspirate mutation (Welsh: treiglad llaes; also called spirant mutation in some grammars). These are also represented in the orthography:

A blank cell indicates no change.

The mutation ts → j reflects a change heard in modern words borrowed from English. Borrowed words like tsips (chips) can often be heard in Wales and the mutated form jips is also common. Dw i'n mynd i gael tsips (I'm going to get chips); Mae gen i jips (I have chips). Despite this the 'ts' → 'j' mutation is not usually included in the classic list of Welsh mutations and is rarely taught in formal classes. Nevertheless, it is a part of the colloquial language and is used by native, first-language speakers.

The word for "stone" is carreg, but "the stone" is y garreg (soft mutation), "my stone" is fy ngharreg (nasal mutation) and "her stone" is ei charreg (aspirate mutation). These examples represent usage in the standard language; there is some regional and idiolectal variation in colloquial usage. In particular, the soft mutation is often used where nasal or aspirate mutation might be expected on the basis of these examples.

Mutation is not triggered by the form of the preceding word; the meaning and grammatical function of the word are also relevant. For example, while yn meaning "in" triggers nasal mutation, homonyms of yn do not. For example: