"Do you know him?"

Translation: Dych chi'n nabod fe?

[ereller]

Why is this answer 'dych chi'n nabod fe' when a previous question I had asked me to translate 'dw i'n eich nabod chi'? Why does the first one not require the possessive pronoun when the second one does?

[daschaich]

There's now a nice discussion on that other sentence. It seems that colloquially the 'eich' can be left out to produce a less-formal form of the sentence, but shwmae says "It's difficult to give precise rules as to when and where each [of the forms] are acceptable."