Where does “vou” come from?

vou (Portuguese) comes from Old Portuguese vou, from Latin vādō, from Latin vadere, from Latin vado, from Proto-Italic wāðō, from Proto-Indo-European weh₂dʰ- — to go, to proceed; to pass, to traverse.

Ancestry of “vou”, step by step

Step	Language	Word	Meaning
1	Old Portuguese	vou	—
2	Latin	vādō	to go, walk, rush
3	Latin	vadere	second-person singular present passive...
4	Latin	vado	I go, walk, rush; I ford, wade through
5	Proto-Italic	wāðō	advance, proceed, go
6	Proto-Indo-European	weh₂dʰ-	to go, to proceed; to pass, to traverse

Every word from Proto-Indo-European weh₂dʰ- →Every word from Proto-Italic wāðō →Every word from Latin vado →