Holy cow, I wrote a book!
My fancy new office phone has an option to change the language of its user interface, so naturally I chose Swedish. Once I did that, I saw some obvious translation errors.
The first example above is just sloppiness, but the second one illustrates how a simple LocalizeString("some text") algorithm doesn't work. As Lance Fisher's teacher put it, "Russian is not a translation of English." You can't just take words and phrases in one language and put them through a simple mapping table and expect the result to be accurate.
Back in the Windows 95 days, the German translation team needed some beta testers, and I volunteered. The most interesting translation bug I reported was one in which an English menu item Sort was translated as Art (which means class, kind) instead of Anordnen (which means to arrange). The one English word has two different meanings, and a blind dictionary translation won't know which one is intended.