I just couldn't help get this nagging feeling of Uhura reading from dictionaries in Star Trek VI ("We is condemning food and things") while talking to the Klingons in this movie. My rationale was that the TUC version of Uhura is stupid and inept and never should have been that way, and this version is much more preferable. A friend of mine even went further to say that maybe prime Uhura did know Klingon when she was younger
Nomad wiped her memory in "The Changeling", remember, and she had to be retrained by Christine Chapel. Uhura may have lost lots of memories from her past.