In Welsh, the preposition must have a suffix (an ending) to match the pronoun that follows it, e.g.
am + nhw = amdanyn (preposition) nhw (pronoun).
i + nhw = iddyn (preposition) nhw (pronoun).
There is no suffix if the preposition is followed by a noun, e.g. chwilio am y dillad, darllen am y bardd.
