Are there any guidelines for the order in which you pile multiple adjectives onto nouns? I.e. "nos dywyll dawel" vs. "nos dawel dywyll".
I believe that we follow the same order as English.
That would mean "Mae hi'n ddu dawel nos." would be correct in Welsh to match the English order?
No the adjectives follow the same order as the English the noun comes before the adjectives unless it is one of the few that comes before the noun.