[Ramius]

Wow... What a fascinating thread. What’s the relationship between Welsh and the other Celtic or Gaelic languages? Similar? Derivative?

[Myrddin]

Celtic languages are in two branches. The Goidelic branch includes Irish Gaelic, Scots Gaelic and Manx (Isle of Man). The Brythonic branch includes Welsh, Breton (spoken in Brittany in the NW of France) and Kornish (spoken around Cornwall). Modern Welsh exists in 3 common dialects. The northern and southern are most common. My family spoke the "mid-valleys" dialect. An example of how different they are:
How are you?
Northern (Sut dach chi?),
Southern (Sut rydy chi?),
mid-Valleys (Shw mae?)