Historical Linguistics and Language Families 9, Exercise 1: Finnish and Hungarian

vesi / víz     Finnish -s-  against  Hungarian -z
käsi / kéz     Finnish -s-  against  Hungarian -z

The same pair of sounds appears in both words, which is what makes it look
like a correspondence set (Chapter 3) and not a coincidence. Two items are a
small sample; the source gives these words as part of its cognate table and
does not state the correspondence in those terms, so this reading is my
application of the method, not a quotation. The initial consonant is more
complicated: Finnish k- against Hungarian h- in kala/hal but k- against k- in
käsi/kéz, which would need more data (and the following vowel) to explain.