At least for French and Spanish since both seem to be recognized as ICAO languages and are spoken in numerous countries around the world. In fact, in my humble opinion the basic aviation phraseology of these languages should even be part of the ATPL exams.
The idea is basically sound.. problem is that when two native speakers converse they speak at a rate and with inflections that are too often just too fast .. My French used to the passable while living there but going through CDG I felt pretty much just as out of the loop as every non- French speaking pilot.
The overwhelmingly dominant international language is English as either peoples first or second language... it's time it was made the only official language of aviation... people using different languages on the same frequency is as absurd and as dangerous as pilots tuning to the wrong frequency... as the aforementioned SH330 crew discovered.