Consonant mutation in Manx

I was intrigued to read recently that the bus company in the Isle of Man is called Bus Vannin (in English), Barroose Vannin (in Manx Gaelic). Vannin is a form of Mannin, the Manx name for the Island. The change from Mannin to Vannin is evidently an instance of a process called initial consonant mutation, which is widespread in the Celtic languages (Welsh, Cornish, Breton, Irish, Scottish Gaelic and Manx). This process changes the initial consonant of a word following particular words.

Here is an example from Welsh. One form of consonant mutation occurs, in singular feminine nouns only, after the definite article y. For instance:

  • cadair (chair) becomes y gadair (the chair)
  • pib (pipe) becomes y bib (the pipe)
  • tref (town) becomes y dref (the town)
  • gardd (garden) becomes yr ardd (the garden)
  • basked (basket) becomes y fasked (the basket)
  • desg (desk) becomes y ddesg (the desk)
  • mam (mother) becomes y fam (the mother)

Here is another example from Welsh. The word Cymru (Wales) becomes Gymru in the phrase Croeso i Gymru (welcome to Wales).

Here is a third example, this time from Irish. This mutation occurs after mo (my), do (your), a (his), though not after a (her). Examples:

  • póca (pocket) becomes mo phóca (my pocket, pronounced mo fóca)
  • carr (car) becomes mo charr (my car, pronounced mo khar)
  • máthair (mother) becomes do mháitair (your mother, pronounced do wáhir)
  • seoladh (address) becomes a sheoladh (his address; pronounced a hyóla)

There is a detailed discussion in Consonant Mutation, by Pavel Iosad, prepared for inclusion in The Blackwell Companion to Morphology. A version dated 29 September 2021 is available at Mutation in Celtic – lingbuzz/006224 (


Welsh, by JT Bowen and TJ Rhys Jones, Teach Yourself Books (1960)

Irish (Teach Yourself Series), by Diarmuid Ó Sé and Joseph Sheils, (1993)


  1. It also occurs in Finnish, with complex and unpredictable rules, as if the language didn’t have enough complications. I still like Finnish, though!

    1. Yes, though the consonant mutation in the Celtic languages happens at the start of words and the consonant changes in Finnish happen mainly in the middle of words.
      I too like Finnish.

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