Feminine singular nouns take a soft mutation after y or r. Nouns starting with ll and rh are exceptions.
| Original | Soft Mutation | |
| p | pont | y bont |
| t | tref | y dref |
| c | coedwig | o'r goedwig |
| b | baner | y faner |
| d | derwen | y dderwen |
| g | gardd | yr ardd * |
| m | merch | y ferch |
* note that yr is used here because the mutated word starts with a vowel.