Phonetic languages are no more the mirror images of each other than are conceptual or social languages. Even languages that are quite close to each other present many difficulties in translation and, of course, as the linguistic gap grows, so accordingly does the possibility of translation. This presents a far graver problem than monolingual persons realize. The theories are not identical from language to language, because the cultural histories are quite different. Reducing discussion to a single language eliminates whole viewpoints.
Dialogue edges toward monologue.
Linguistic diversity has all the merits attributed to biological diversity. It is equally worth preserving and is equally something of which we must avail ourselves actively in order to maximize scientific gain. This would suggest that every scholar ought to utilize effectively a very large number of languages, logically all languages. But, as with most processes, after a certain point, the marginal gain would not be worth marginal cost. The question of costs is of course very relevant.