When Do I Use Soft Mutations In Welsh?

Hi everybody,

I'm just not exactly sure when to use soft mutations in Welsh?

If anyone could help, you're awesome!

May 26, 2018


Some situations I know of where you use the mutation;

  • After “y(r)” for feminine nouns only (masculine nouns are not mutated).

  • When asking “May I have....?”

  • After prepositions and possessives.

Basically any situation where softness works in your favor.

Some examples found here;

May 26, 2018

"Basically any situation where softness works in your favor."

Could you explain what you mean by that exactly? If there's an easier way of remembering when to use mutations, I'm all ears!

May 27, 2018


May 27, 2018

Just to add some more detail --

  • only singular feminine nouns are mutated following the definite article (yr / y / 'r), not plural nouns: y ferch, but y merched
  • adjectives following singular feminine also mutate: merch fach
  • nouns following the adjective hen ("old") softly mutate (and the adjective itself is 'irregular' as it precedes the noun): yr hen ddraig
  • ordinal numbers used with feminine nouns will mutate softly, as will the noun: y bumed ferch
  • most prepositions, but not all, cause the following noun to softly mutate. Some common prepositions that cause this mutation are i, o, am, and ar, while some that cause other mutations are â and gyda
  • the conjunction neu ("or") also causes a soft mutation: llaeth neu ddŵr
  • only the possessives dy (singular "your") and ei ("his") cause a soft mutation: dy gath (di), ei gath (e)
  • when used in a possessive construction, gan causes the owned noun to mutate: mae gen i gar
  • the numerals un ("one") and dwy (feminine form of "two") cause feminine nouns to mutate: *un ferch, dwy ferch)
  • the numeral dau (masculine form of "two") causes masculine nouns to mutate: dwy fachgen
  • adjectives and nouns following yn undergo a soft mutation: mae'r ddraig yn fawr
  • related to the above, adverbs formed from adjectives using yn undergo a soft mutation: yn fwriadol
  • dyma and dyna cause a soft mutation: dyma gi
  • most negative short-form verbs in the past and future tenses will undergo a soft mutation: ddarllenais i mo'r llyfr
  • the indefinite object of short-form verbs in the past and future tenses will undergo a soft mutation: darllenais i lyfr
  • many adverbs of time use soft mutations: ddydd Llun, ddwywaith y mis

This is far from exhaustive but it's everything I could think of, and hopefully covers some of the more common rules.

May 27, 2018

thank yoooooo!!! :)

May 27, 2018

There are 40-ish causes of soft mutation of initial consonants in Welsh, only some of which are covered on this introductory course. Any good Welsh grammar book will explain them.

For an explanation of some common ones, look at the mutations section of the introductory 'BBC Learn Welsh Grammar Guide' - has a .pdf version. A more comprehensive grammar book is 'Welsh Rules' by Heini Gruffudd.

May 27, 2018

I tallied them up when making flashcards for myself. 42 was the number I counted, and it made me wonder if Douglas Adams was Welsh... but, sadly no.

May 29, 2018

Da iawn. I'm sure that the number varies according to you define and group them, but 42 is a good number to quote to people, and we now know what the ultimate question really is!

May 29, 2018

Sweet as, thanks! You're the best!!!!!!!

May 26, 2018
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