Mutations in Brithenig
These are very important in Brithenig. There are three initial mutations in Brithenig: soft mutation, spirant mutation, and nasal mutation.
Soft mutation is the most common and is used initially with feminine nouns, adjectives and verbs, changes in sentence order or after an adverb, and the prepositions di, of, from, and gwo, under, beneath.
Spirant mutation marks nouns, adjectives and verbs as plural, it is also used with the prepositions tra, through, and a, to, at, and the conjunction mai, but. The infinitive of a verb is speech normally undergoes spirant mutation, unless the preceding verb was an auxiliary verb.
Nasal mutation is used with the negative adverb rhen to mark verbs as negative, it is also used with the preposition in, in, into and cun, with. In Brithenig the mutations are called cluinediwn, declensions, and are described as moillad, softened; solwed, loosened; and naral, nasal.
Table of Mutations
| radical | Soft | Spirant | Nasal |
| p | b | ph | mh |
| t | d | th | nh |
| c | g | ch | ngh |
| b | f | f | m |
| d | dd | dd | n |
| g | 0 | 0 | ng |
| m | f | f | n/a |
| ll | l | l | n/a |
| rh | r | r | n/a |
Hard 'g' always becomes silent when it is softened. If the 'g' is an afficative, pronounced like the 'j' in jam, as before the vowels 'i' and 'e', then the 'g' is not softened. Likewise 'c' before a front vowel becomes 'g', with the j-pronunciation when it is softened. 'C' before 'i' or 'e' does not undergo spirant mutation, but may soften in those circumstances.
What causes mutations? Mutations are caused by the loss of sounds at the end of preceding words. A word ending in a vowel, such as the -a ending of feminine article, noun, or adjective causes the next word to soften. For the most part these vowels have been lost, except in a few one-syllabled words, such as pronouns, articles and prepositions. (Note that the Romance masculine ending -o had been lost before this softening started to take place.) Spirant mutations are caused by an original -s on the end of words that became -h before it vanished but still affects following words.
The exception to this rule is the preposition a from latin `ad', where the final -d became assimilated in sound with the consonant following it, and then the cluster underwent spirant mutation. In the modern language this rule has become irregular and dropped. Before a vowel the preposition a and the conjunction e' are more likely to add the ending -dd, becoming a-dd and e-dd.
Nasal mutation is caused by nasal consonant ending the preposition, or the lost negative participle `non'. Even though the -n or -m is still written, it is pronounced the same as the nasal mutation following it.
