Cadê in Portuguese

Is this really Portuguese?

Sim, é.
You will hear it every day in Brazil.

And for some reason, it's not presented in any of the Brazilian Portuguese grammar books or other learning materials! Probably because it's relatively recently become part of the common (conversational) vernacular. But it's omnipresent. In conversational Portuguese, Brazilians will use CADÊ in place of onde está or, aonde foi? extremely frequently. It's not slang -- it's become part of the language*

Cadê in Portuguese = onde está.

The pronunciation is like você in that the 'e' is pronounced 'AY': CA-DAY

Let's see it in action:

Cadê você? »  Where are you?
Cadê meu carro? » Where’s my car?
Cadê seu telefone? » Where’s your telephone?
Cadê sua irmã? » Where’s your sister?
Cadê seu amigo? » Where's your friend?

It evolved from  o que é de…? >> que é de? >> quedê? >> cadê?