Welsh Initial Mutations: An FST Analysis

Ingo Mittendorf & Louisa Sadler
University of Essex

(ingo.mittendorf@btopenworld.com / louisa@essex.ac.uk)

For the Welsh part of the project Verb Initial Grammars: a Multilingual/Parallel Perspective [1] we have been developing a morphological analyser using Xerox Finite State tools (xfst, lexc). The morphological analyser is integrated into the Xerox Linguistic Environment (XLE) platform which we use to write our Lexical Functional Grammar (LFG) based grammar of Welsh. All of this is work in progress.

One of our first challenges was the Welsh system of Initial Mutations: the initial phoneme of a word regularly alternates with other phonemes in several sets called "initial mutations". These different initial mutations appear in specific lexical or syntactical environments. The following table gives some examples, together with a trigger (the preceding possessives):

Radical   Soft Mutation Nasal Mutation Aspirate Mutation
    'his X' 'my X' 'her X'
ci 'dog' ei gi fy nghi ei chi
gardd 'garden' ei ardd [2] fy ngardd ei gardd
mam 'mother' ei fam fy mam ei mam

The main challenge with such regular cases is the right rule ordering (note the various identical initial <g>'s in the table).

However, there are other complications:

  1. some words trigger hybrid mutations;
  2. some words completely "resist" being mutated;
  3. some words undergo some mutations but not others;
  4. there are completely idiosyncratic mutations such as the Nasal Mutation of blynedd 'years' after certain numerals;
  5. phonemes not undergoing overt mutation (/n/, /s/ etc.) cannot be left outside the system in our constraint-based approach (LFG).

1-3. can be solved by exploiting the possibilities of xfst and lexc, and 4. turns out to be unproblematic; 5. leads us to approach the whole system of Initial Mutations in a way that differs from many other approaches.


  1. We are grateful for the financial support of the ESRC (research grant RES-000-23-0505) for this project.
  2. = /g/ ~ zero