If you take Equestria Girls into consideration, there may be even less of a language barrier than you might think. That, of course, is assuming you're considering those movies to be canon. I do, personally, because at no point do they ever contradict the show. But I also know there are plenty people who vehemently consider them to be purely spin offs that aren't canon. I will say in defense of the EG movies that Shadow Play does explicitly have a scene of Starswirl banishing three very familiar looking Sirens (obviously the Dazzlings from the second movie) so... grain of salt?