My understanding is that it is considered unsafe for a transmission to be translated into english from the local language by the person transmitting, then translated back into the mother tongue from english by the person receiving, which could give rise to misinterpretation of instructions or clearances, particularly clearances.
I don't have a problem with this as for example, I would prefer the traffic I see on TCAS to know to which level he/she has been correctly cleared without any confusion, instead of everyone else "on freq" hearing about a level bust in perfect english.
Not ideal, but on balance I prefer the status quo.