[oeuviz]

How come the same situation is present in other languages(e.g. French, Serbocroatian)? Improbable that it were always the Normans.

[BerislavLopac]

Which situation specifically? Serbo-Croatian doesn't have that differentiation between the name of the animal and of its meat. There are others (regional "astal" being my favourite example), but the similar pattern can happen in any language.