Given the situation of a Wikipedian using Google to translate compatibly licensed content, it is very unlikely that the use of that content on Wikipedia violates any Google copyrights. Assuming that any derivative copyright attaches, it is most probable that the Wikipedian would own it. Since the source material is presumably available by CC-BY-SA 3.0 or a similar license, the translated work would be safe for use on Wikipedia as long as its source is properly attributed.

(Text is available under the Creative Commons Attribution-ShareAlike License)

meta.wikimedia.org/wiki/Wikilegal/Copyright_for_Google_Translations