Appendix:Welsh mutations

Welsh, like all modern Celtic languages, is characterized by its initial consonant mutations. These mutations affect the initial consonant of a word under specific morphological and syntactic conditions. The mutations are an important tool in understanding the relationship between two words and can differentiate various meanings.

Welsh uses three mutations on consonants: the soft mutation (segment becomes voiced/lenites), the nasal mutation (segment becomes nasal), and the aspirate mutation (also called spirant mutation). Words beginning with a vowel are subject to h-prothesis under certain circumstances. Some sources consider h-prothesis of vowels to be a form of aspirate mutation, but since the environments of the two mutations are different, it is preferable to consider h-prothesis and aspiration two different mutations.

The unmutated form, i.e. the “basic” form that dictionary entries are listed under, is known as the radical.

Effects of the soft mutation
When under soft mutation, radical consonants lenite to voiced and/or fricative segments (/v ð/), as shown below:

† – the mutation of Welsh ts → j is only found in the colloquial language and will not be found in the literary register. It is found only in loanwords from English, i.e. chips is rendered as tsips in Welsh and with the mutated form jips – for example, mae gen i jips.

All other Welsh consonants do not change under the soft mutation.

Environments of the soft mutation
Soft mutation occurs in an enormous number of very different environments in Welsh. The following list is representative but not exhaustive.

After certain determiners
The definite article, , triggers soft mutation of a feminine noun or adjective in the singular:

In nouns, ll and rh never undergo soft mutation after the article, although they do in adjectives:
 * , although is feminine singular
 * , although is feminine singular
 * (referring to a feminine singular noun)

The possessive pronouns of the 2nd person singular and 3d person masculine singular  trigger soft mutation:

Nouns undergo soft mutation after, , and :

After a predicate particle
The predicate particle triggers soft mutation of a noun or adjective, except ll and rh do not undergo soft mutation here: The verb form triggers soft mutation of a predicate noun or adjective:

After certain adverbs
There is no soft mutation of ll and rh after, and :

After certain preverbal particles
Note:, , and trigger aspirate mutation of p, t, c and soft mutation of all other mutable consonants. This is known as mixed mutation.

Between nouns and their modifiers
Feminine nouns only are mutated after, but in nouns ll and rh are not (though they are in adjectives): When means “similar” it triggers soft mutation of both masculine and feminine nouns in the singular: After and, both feminine and masculine nouns are mutated: After other ordinal numbers, only feminine nouns are mutated:
 * After certain numbers
 * (referring to a feminine singular noun)
 * (referring to a feminine singular noun)
 * (referring to a feminine singular noun)
 * (referring to a feminine singular noun)
 * is masculine

An attributive adjective usually follows its noun in Welsh, but when the noun follows the adjective, it undergoes soft mutation. An exception is, which does not trigger soft mutation, and other preposed superlative adjectives do not necessarily trigger it.
 * After preposed adjectives

There is no soft mutation of ll and rh after n and r:
 * The second part of a compound

Exception: d does not mutate to dd after s, e.g..
 * Attributive adjectives after a feminine singular noun

This rule is applied sporadically in the case of proper names, and is also found.
 * Nouns in a genitive construction after a feminine singular noun
 * (from )
 * (from )
 * (from

There are many exceptions to this rule, e.g.
 * Attributive adjectives after a proper name when used as an epithet


 * Numbers following a plural noun for literary effect

Soft mutation without a trigger in the same phrase

 * The direct object of a finite verb, including, , :


 * The equative used exclamatorily


 * Various nouns and adjectives used adverbially


 * A noun in apposition to a noun or pronoun
 * (from )
 * (from )


 * Nouns in the vocative


 * Forms of starting with b- after a stylistically fronted predicate


 * Verbs expressing an opinion or belief used parenthetically

Negated sentences take the mixed mutation, so p t c undergo aspirate mutation, not soft mutation, here. In questions, all mutable consonants undergo soft mutation.
 * A verb at the beginning of a question or negated sentence (colloquial language)


 * A word after an interpolated prepositional phrase (including a conjugated preposition) or adverb

Effects of nasal mutation
A voiceless stop becomes a voiceless nasal, while a voiced stop becomes a voiced nasal.

The other consonants and the vowels do not change under nasal mutation.

After the determiner
The possessive determiner triggers nasal mutation:

Colloquially, may be reduced to  or deleted altogether (but still marked with an apostrophe); in both cases, the nasal mutation remains:

After the preposition
The preposition assimilates to  before a bilabial consonant and to  before a velar consonant.

Certain time words after certain numbers
The words, , and undergo nasal mutation after the numbers , , , , , , , , , , and their compound forms. Blynedd and blwydd also undergo nasal mutation after in composite numerals (i.e. where another number follows the noun to complete the meaning):

In most cases, only nouns (including verbal nouns) can undergo nasal mutation. The only exception is adjectives that are placed before the noun they modify:
 * (no mutation of the possessive determiner )
 * (no mutation of the possessive determiner )

Effects of the aspirate mutation
Under aspirate mutation, voiceless plosives become voiceless fricatives:

The other consonants do not change under the aspirate mutation.

Vowel-initial words are sometimes said to undergo aspirate mutation by adding a prothetic h, but since the environments are different for vowels than for consonants, h-prothesis will be discussed separately below.

After certain modifiers
The possessive determiner / (also ) triggers aspirate mutation:

The numerals and  trigger aspirate mutation:

The adverb triggers aspirate mutation:

After certain preverbal particles
Note: and  trigger aspirate mutation of p, t, c and soft mutation of all other mutable consonants. This is known as mixed mutation. The particle may be omitted, but the aspirate mutation remains:

H-prothesis
H-prothesis is the addition of h to a word starting with a vowel (including i when pronounced ).

The possessive determiners and infixed pronouns, / (also ), /, and / trigger h-prothesis:

When precedes a verb form as its direct object, it triggers h-prothesis even when it’s masculine singular:

The preposition triggers h-prothesis of  in complex numerals: