I was going to ask you this by private, but since it's vaguely word-related:

I'm curious, since Yom Kippur is [in my very limited understanding] the most somber and solemn Jewish celebration, I have two questions:

(1) "Celebration" obviously isn't the right word for it. What is?

(2) How would one typically acknowledge the event with a fellow believer? For example, if you spoke with your mother this morning you most certainly wouldn't wish her a 'Happy Yom Kippur', as in Happy Easter, Merry Christmas, etc., right? Wishing someone a "solemn yom kippur" would seem a bit odd as well, though. Is there a pat expression that's used?

In the Catholic church we avoid such confusion on our most somber day, Good Friday. During the hours that represent Christ's suffering on the cross, we don't speak at all.