"Some foreigner probably translated that sentence."
Translation:Tu větu asi překládal nějaký cizinec.
That is fine as well. To me, but I must say that the mods don't seem to accept my reports... Slightly different part of the declaration is stressed so it is not the first basic option.
You would use it, for example, when you have some sentence for translation somewhere (on thew like Duolingo) and you notice that some foreigner probably translated the sentence.
The official answer is when you have a sentence and it looks strange so you conclude that it was probably translated by a foreigner.