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  • mutant.jpg From the Wikipedia : "Welsh, as with all other Celtic languages, often sees changes made to the beginning of words depending on the word that precedes it, or the role it plays in the sentence. These changes are known as "mutations", of which Welsh has three distinct types. Common situations in which a mutation may occur are when a word follows a preposition, possessive, or number."

    The three types of mutation are:-

    Soft Mutation

    Nasal Mutation

    Aspirate Mutation

    The three links will take you to further information (see below) about these commonly occurring mutations.

    Most Welsh courses and teachers advise students not to worry too much about mutations at the outset. Fluent speakers will understand you if you forget to mutate a letter. With practice this will come naturally and there is perhaps, no need for beginning learners to make a conscious effort to apply these rules. It is important to remember, however, that mutations, "...pervade the entire structure of the language, and cannot be divorced from any aspect of it. These initial changes to words are as integral a part of Welsh as, say, the endings to words are in German or Russian." *

    If you are determined to master the rules early on you could look out for the 'Mutant Alert' notice on the vocabulary pages and use these as an opportunity to refresh your knowledge by checking the links.

  • Possible Mutations


    First Letter

    p t c b d g m ll rh

    Soft Mutation

    b d g f dd omit g f l r

    Nasal Mutation

    mh nh ngh m n ng - - -

    Aspirate Mutation

    ph th ch - - - - - -

    . .

    As you can see in the above table, there are nine consonants which undergo mutation in Welsh. There are three classes of mutations and different rules governing their use. 

    Soft Mutation


    1. When the definite article ( y before a consonant or yr before a vowel) is used before a feminine noun the noun undergoes a soft mutation (this rule does not apply if it begins with ll-  or  rh- ).

      When using the article before a masculine noun, soft mutation does not occur.

      e.g.  bachgen = boy ( n.m. )  Mae'r bachgen wedi seiclo yma. - The boy has cycled here.

      When using the article before a feminine noun, soft mutation occurs.

      e.g.  merch = girl ( n.f. )  Mae'r ferch wedi seiclo yma. - The girl has cycled here.

                  2. Adjectives which follow feminine nouns also undergo mutation.

                  e.g. tal = tall  Mae'r ferch dal wedi seiclo yma. = The tall girl has cycled here.

        3.  Most Welsh prepositions require a soft mutation. See list below:

                   am - ar - at - dan - dros - drwy - gan - heb - hyd - i - o - wrth


       dros y penwythnos = over the weekend  

       dros benwythnos = over a weekend

       The Welsh word for course is cwrs . The Welsh phrase for 'of course' is wrth gwrs . Note the soft          mutation.

       4.  The possessive pronouns 'your' (singular, familiar) = dy.....(di)   and 'his' = ei...(e/o) require soft         mutation.


      llaw = hand

      ei law...(e/o) = his hand

      troed = foot

      dy droed....(di) = his foot

      Ei also means 'her', but when so used it requires an aspirate mutation. (see below)

      5.   Immediately after a command.

      Rhowch ryddid i mi neu rhowch farwolaeth i mi! = Give me freedom or give me death!

    It should be noted that the above list is not exhaustive. There are more than 30 rules governing the use of soft mutations in Welsh. For a complete list go here:- Soft Mutation Rules ,,,



    Nasal Mutation

    180px-Exclamation_encircled.svg.png 1. A nasal mutation occurs after use of the preposition yn (in). Yn does not cause mutation when used as a particle before a verb.  Example:

        If you were born in Cardiff (Caerdydd) and live in Portland (Portland) you might want to say:

       "I was born in Cardiff but I live in Portland.'

       This construction requires nasal mutation as follows (you will find help with pronunciation in the              soundfile above):

       ' Cefais fy ngeni yng Nghaerdydd ond dwi'n byw ym Mhortland.'


       2. A nasal mutation also occurs after  fy . The word  fy (my), causes nasal mutation in the words              listed below:

        dillad - clothes

        brawd - brother

        tadau - fathers

        fy nillad  - my clothes

        fy mrawd  - my brother

        fy nhadau  - my fathers

        Sometimes, in the spoken language, fy is omitted entirely. 


    Aspirate Mutation


    1.  After  "a"   a  is the Welsh word for  and  ( ac  is only used before vowels, hence it cannot cause an aspirate mutation).


      ffiseg - physics

      cemeg - chemistry

       ffiseg a chemeg - physics and chemistry

      radio - radio

      teledu - television

        radio a theledu - radio and television


       2. The pronoun  ei  ( her ) causes  aspirate mutation.


        potel - ei photel

        cinio - ei chinio

        taith - ei thaith .


    Mixed Mutation


    1.   Ni , na and oni  cause aspirate mutation of c, p and t and soft mutation of all other mutable consonants. 


       Pam na chymerwch bum munud i feddwl amdano?

                Why not take five minutes to think about it?


    * Gareth King: Modern Welsh A Comprehensive Grammar p. 13