You forgot Russian "ПРОБКЕ"(PROBKE) and Polish "Próbnik" and probably many, many others:tiphat: This "sonda, sonde" thing might have something to do with languages families I think, although in Polish "Sonda" also mean probe but this word might be simply adapted from some foreign language.
I think it has to do with roots. The 'sonde' words all seem to come from the same root meaning 'sounding line'. Consider it's similarity to Old English sund-, which meant water or sea. A sounding line was a weighted rope that was used to measure depth in the waters around ships. They would drop the weight in and go until it reached the bottom, acting as sort of a 'probe' in the water I suppose. I'm assuming that was the train of thought when they chose to use that word for a probe.
The English 'probe' comes from Latin, and as far as I can tell, it originally comes from the Latin verb 'probare', which meant to test or prove. probare itself came from probus, also Latin, which meant 'worthy, good, upright, virtuous'. One source I checked also said that probus could be traced back further to a Proto-indo-european family, and the word 'pro-bhwo', which meant 'being in front'. I don't see the connection, but I'm no expert. Anyway, probare gave rise to 'proba' which was, in the Renaissance, an instrument for exploring wounds. I guess this instrument was so often associated with medical 'examination', that it just took on that name.
In a general sense, yes, they come from different families, one being Latin and the other Germanic, but it's really a matter of how they saw the instrument. I think that, in many of the languages that use the 'sonde' forms, the verb 'to prove' will be very similar to 'probe'. They just didn't choose to name the object after that verb. :tiphat: