mazurzenie

The replacement or merger of the Polish language's series of retroflex fricatives and affricates /ʂ, ʐ, t͡ʂ, d͡ʐ/ (written ⟨sz⟩, ⟨ż⟩, ⟨cz⟩, ⟨dż⟩) into the alveolar series /s, z, t͡s, d͡z/ (written ⟨s⟩, ⟨z⟩, ⟨c⟩, ⟨dz⟩), present in Masovian and other dialects.