
Latin word nego comes from Proto-Indo-European *h₁eǵ-, and later Proto-Italic *agjō (To assert.)
*h₁eǵ- (Proto-Indo-European)
*agjō (Proto-Italic)
To assert.
aio (Latin)
I say, I assert, I say yes, I say no, I affirm, I assent.
nego (Latin)
(intransitive) I refuse, say no. (transitive) I reject, refuse, say no to (something). I deny. I keep from, prevent.