Changing accents?

[Elennar Starfire]

Although, I felt Dom Monaghan was the most convincing of the four hobbits .... I half hoped that Merry might have a slightly Welsh accent, because of Buckland representing the "celtic" fringe of the Shire. But I guess that to have Welsh and Scottish would be too much.

Too much? Nay, indeed 'twould never be enough.
(at least for such people as myself...but then, I'm very strange...)

I think I've heard an explanation of Pip's Scottish accent, having something to do with hints of the Tooks being Scottish; one point was their invention of Golf. It might have been on the extras of the FotR DVD...

The director's commentary perhaps? I remember that, though not where it was. I'm fairly sure it was in a commentary.