Why is the German "qu" pronounced as "kv"? Most of the languages I know of pronounce "qu" as "w" and/or "kw". What's the history behind this oddity?
Why do you think it's an oddity?
The sound [w] (as in the English words "wind" [wɪnd] or "weep" [wiːp]) does not exist in German language. The most similar sound that exists in German is [v].
And in English I didn't find any word where "qu" was spoken other than [kw]:
- consequence [ˈkɒnsɪkwɛns]
- quick [kwɪk]
- request [ɹɪˈkwɛst]
- quality [ˈkwɒlɪti]
- quarter [ˈkwɔːtə]
- squad [skwɒd]
So, beside the general usage of [v] instead of [w] the German pronunciation is the same like in English.
Middle High German had a phoneme /w/, usually written “w”, and did not have the sound [v]. In New High German this /w/ survives in a very small number of words (I can think of “blau” and "grau"); otherwise it shifted to /v/, but retained the old spelling with “w” or “qu”. The development of “qu” to /kv/ is thus exactly parallel to the development of “w” to /v/.