In English, we've got terms like "mother-in-law," which is accurate, but fairly dry and clinical. In contrast, in French you've got "belle mere" or "beautiful mother," which is maybe a bit more vague, but has some flavor to it, some connotation. (Or Korean, in which, as far as I can tell because I don't speak it, you have the words for "mother" or "father," but with a more formal suffix?)
What are some words for in-laws in different languages? Particularly: "in-laws" (as a group), "mother-in-law," and "father-in-law." Endearments, euphemisms, pet names? (And may I ask for the English approximations as well?) It's okay if a language differentiates between paternal and maternal relatives.
EDIT: Any quirky etymology (or hints on where to find it out) also appreciated.
Thanks so much for your input!