To me the pairs "mihin/minne" and "koska/milloin" have exactly the same meanings, respectively. Maybe it's a regional or dialectical thing, which one to use (I'm from the Helsinki region).
So, to me, the following mean exactly the same:
Mihin olet menossa? Minne olet menossa?
Where are you going?
Same for these:
Milloin tulet? Koska tulet?
When will you come?
However, those are fairly general questions. Mihin does have also the specific (or more precise) meaning into what/which?, when going physically inside something. It is in fact the question word "mikä" in illative case.
Mihin noista taloista aiot muuttaa?
Into which one of those houses are you moving?
But you can't say: Minne noista taloista aiot muuttaa?
But this is ok: Minne aiot muuttaa? (Where are you going to move?)
I think the meaning is different from the more general "where to" meaning, which "mihin" also has.
Last edited by Miumau
on 2011-08-26, 15:51, edited 3 times in total.