Initial consenant mutation – Altering the beginning of a word/and or the end in certain grammatical situations.
The following is stolen from a random .doc found floating on the internet.
Note: You`ll see the following symbols (s), (n) and (a). These show you that a sound change potentially follows. These symbols are not, used when writing Welsh. They are used to help you notice and come to understand the sound changes. They are to help you as you learn. The sound changes are:
TM(s) Treiglad Meddal (SM soft mutation) Very common in native speech.
TT(n) Treiglad Trwynol (NM nasal mutation) Very limited in native speech.
TL(a) Treiglad Llaes (AM aspirate mutation) Very limited in native speech.
The Welsh word `treiglo` was translated as `to mutate` when discussing the sound changes in Welsh. Given one modern usage of the word `mutate` in English, this has unfortunate connotations. It could have been translated as `to turn, roll, tumble, whirl, change, circulate, spread, move, roam, wander, meander, flow, trickle` etc. So you could think of the sound changes as a soft meandering, a nasal meandering and an aspirate meandering of sounds!
In Welsh, some sounds at the beginnings of words change. (There`s more to it than this as sounds also change in the middle of words and at the end of words, but we don`t need to learn these changes here.) These sounds and the sounds they change into are outlined below. For example, `p` (the sound `puh`) can change into `b` (the sound `buh`), `t` (the sound `tuh`) can change into `nh` (the sound `n-huh`), and `c` (the sound `kuh`) can change into `ch` (the sound `ch-uh` with `ch` as in German `Bach`). The sounds are represented by letters in writing.
You`ll hear native speakers talking or you`ll read something and notice that the sounds have already changed. Remember the principles of reverse engineering. So if you hear `buh` or read `b`, the sound might come from `puh`. Similarly, `n-huh` or `nh` from `t`, and `ch-uh` or `ch` from `kuh`.
Remember that these are potential sound changes. For example, potentially, a sound change (TM) can occur to the sound immediately following `i` meaning `to/for` if the immediately following sound is one of the nine shown on page 2. If it`s not one of the nine, in other words if it`s not on the list, then no sound change happens. The same applies for TTn and TLlh.
Dw i`n mynd i(s) Genarth