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A little change. A useful skill.

Welsh Mutations / Treigladau Cymraeg

A simple, interactive guide to how letters change in Welsh.

A mutation changes the beginning of a word. Start with the letters, see them in context, then have a go yourself.

01 · The letters

Interactive mutation chart

Choose a mutation to see which initial letters change. Red marks the result. Welsh ll and rh each count as one letter.

Soft Mutation / Treiglad Meddal
OriginalMutated result
pb
td
cg
bf
ddd
g-
mf
lll
rhr

Nine initial letters change. When g disappears, the rest of the word stays.

Nasal Mutation / Treiglad Trwynol
OriginalMutated result
pmh
tnh
cngh
bm
dn
gng

Only p, t, c, b, d and g change under nasal mutation.

Aspirate Mutation / Treiglad Llaes
OriginalMutated result
pph
tth
cch

Only p, t and c change under standard aspirate mutation.

02 · In context

Small changes, real words

Here is an example for every change above. The meaning of the noun stays the same; the word before it triggers the mutation.

Soft Mutation

After dy (your):

  • pen → dy benyour head
  • tad → dy dadyour father
  • ci → dy giyour dog
  • brawd → dy frawdyour brother
  • desg → dy ddesgyour desk
  • gardd → dy ardd (g disappears)your garden
  • mam → dy famyour mother
  • llaw → dy lawyour hand
  • rhaw → dy rawyour spade

Nasal Mutation

After fy (my):

  • pen → fy mhenmy head
  • tad → fy nhadmy father
  • ci → fy nghimy dog
  • brawd → fy mrawdmy brother
  • desg → fy nesgmy desk
  • gardd → fy ngarddmy garden

Aspirate Mutation

After ei (her):

  • pen → ei phenher head
  • tad → ei thadher father
  • ci → ei chiher dog
03 · Your turn

Practise a little Welsh

Answer 20 questions and see your score at the end. Choose the correct mutated form. Take your time — there is no timer.

04 · Keep it handy

Welsh mutations: quick reference

Soft / Meddal · Nasal / Trwynol · Aspirate / Llaes

Soft Mutation / Treiglad Meddal
OriginalMutated result
pb
td
cg
bf
ddd
g-
mf
lll
rhr
Nasal Mutation / Treiglad Trwynol
OriginalMutated result
pmh
tnh
cngh
bm
dn
gng
Aspirate Mutation / Treiglad Llaes
OriginalMutated result
pph
tth
cch

Only the initials listed in each chart change under that mutation. Soft mutation removes initial g. Other letters remain unchanged in these standard consonant mutations.

Common triggers: soft after i, o, dy, ei (his); nasal after fy; aspirate after ei (her) and a (and). This is a quick reminder, not a complete set of rules.

The Bald Welsh Teacher · baldwelshteacher.com