EN
Apart from the derivation used in vocabulary expansion where derivative В with a meaning z2 is concomittant to the stem A with a moaning z2 e.g. kawa > kawiarnia we come across a derivation which assimilates or revives particular function of the types where derivative В with a meaning z replaces stem A with the same meaning z, e.g. former word zbrodzieti, a modern one zbrodniarz, or władczyna - władczyni etc. The first type of derivation car. be called multiple derivation, the other one - substitutional derivation. The latter, as a matter of fact, can be found only In diachronic studies. Tbus, the forms władczyni are, synchronicaily speaking, multiple derivatives and in diachronic sense they are substitutional. The role of substitutional derivation in the Polish language history is of considerable imrortance. It is used, first of all, for secondary differentiating of those functions of a formative which have originally been inadequately differentiated.