In re-reading Prolegomena to Any Future Metaphysics, for the first time more than thirty years, I noticed that I had forgotten just how unsatisfactory translations from German can be. I should say that this translation is better than some such that I have seen, where the translator tries to follow the German syntax, turning what likely is difficult yet acceptable German into barbaric English. The English is not graceful, but perhaps could not be, and anyway grace is not the first quality I want in a translation of Kant. What made me uncomfortable was the regular suspicion that precision had been lost: for example, were certain concepts "mentioned" above, or were they enumerated? Does this "concept" translate the same German word as that "concept" does? This is not only a problem with translations from German: read Aquinas's On Being and Essence, and amuse yourself guessing whether any given appearance of the word "being" renders "ens" or "esse".
One finds the same problem in other kinds of writing. I'm confident that I know of a few careless mistakes in translations I've read of histories, for example of Marc Bloch's Strange Defeat and of Jules Halevy's The End of the Notables. One counts on mistakes in translations of fiction, and never expects too much from translations of poetry. Yet in history, which proposes to narrate and interpret events, and in philosophy, which offers to explain pure thought, one would like to demand precision, or at least consistency, and to imagine it as possible.
Now and then I wish that the teachers at my schools had said, not "you're supposed to take a foreign language" or "we require five quarters of a foreign language, and recommend French," but something different. Perhaps "You will find that there are important books you must read, which were written in this language; there are better translations and worse translations, but really you will wish to be able to read the book in the original, if only to check the translation." But maybe they said something like that and I didn't listen.