By the way, we consider them unique letters, not A and O with diacritics. The Swedish alphabet goes …XYZÅÄÖ.
Oh, and I just learned that we only officially added W in 2006. Before that, it was considered a variant of V. We still pronounce them the same, which is why many swedes will mix them up when speaking English. Mostly in the W->V direction, but I've heard the opposite happen too.