For the Welsh part of the project Verb Initial Grammars: a Multilingual/Parallel Perspective  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 ||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:
1-3. 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.