Where does “canwyr” come from?

canwyr (Welsh) comes from Welsh canu, from Middle Welsh canu, from Old Welsh canam, from Proto-Brythonic kėnɨd, from Proto-Celtic kaneti, from Proto-Indo-European keh₂n- — to sing.

Ancestry of “canwyr”, step by step

canwyr traces back through two separate lines of ancestry.

via Welsh canu

Step	Language	Word	Meaning
1	Welsh	canu	to sing; to intone, chant; to state, say
2	Middle Welsh	canu	to sound
3	Old Welsh	canam	—
4	Proto-Brythonic	kėnɨd	to sing
5	Proto-Celtic	kaneti	to sing
6	Proto-Indo-European	keh₂n-	to sing

via Welsh ŵyr

Step	Language	Word	Meaning
1	Welsh	ŵyr	Soft mutation of gŵyr; grandson, grandchild
2	Middle Welsh	wyr	Soft mutation of gwyr

Every word from Proto-Indo-European keh₂n- →Every word from Proto-Celtic kaneti →Every word from Proto-Brythonic kėnɨd →