Þið

I have always lamented that English does not have a plural you, no way to distinguish between you meaning one person and you meaning all of you (unless one says y'all, which one might sometimes say but never write). Icelandic on the other hand has a plural you, þið. For some reason I have a much easier time with using this word in its accusative, dative, or even genitive case, rather than in the nominative. When I say something that would translate as, 'Are you plural going to do that?', it comes out instead as 'That is going to you' or God knows what, because I say, 'Ætla ykkur að gera það?' instead of 'Ætlið þið að gera þetta?' After all this time, I finally get to use a plural you, and boy I wish I could do it right.