Ahhhh Brazil, so Portuguese? Damn, I had no idea.
Well soz for yelling about it then :P My bad.
Not sure how you get Kate from Keith, but I guess if your language pronounces the E in Keith, more like the Japanese A sound E sometimes makes, and the H is silent... hmmm... I guess that might be it. The Kei being pronounced like the Japanes kei, as Kei Car.... with a T on the end, but actually a Th, with a silent h, yeah?
HA! That would F with anglophones SO MUCH bwhahahahahahahahha. I am middle aged Aussie bloke from outback Aus, and when I see the name Keith, it basically makes me think of leathery old bloke in overalls covered in grease wearing a bright orange toweling bucket hat and 40 year old Seiko watch with a long, oil stained rag poking out one pocket, and pouch of White Ox tobacco peeking out the other.
Not some voluptuous flirtatious goddess lol bawhahahaha. Thanks for indulging my fascination.