Cadê is probably one of those most useful and most entertaining words to learn in Portuguese, because of its straightforward usage and easy pronunciation. It means “where is…” followed by the object. This can be an actual object or a person. This is a Brazilian expression that emerged from a language evolution from “o que é de…” to “quedê?” to “cadê?” Quedê is still used in some parts of Brazil, but you will most frequently hear cadê.
Cadê meu livro? Where’s my book?
Cadê o seu casaco? Where’s your coat?
Cadê a tua mãe? Where’s your mom?
Cadê você? Where are you?
We can also use cadê alone to mean, “Where is it?” We use this if we haven’t understood where the object is, or if we still can’t find the object.
O livro está lá embaixo da mesa. The book is under the table.
Cadê? Where/Where is it?
When referring to a person, though, we can also use the expression onde estar. Estar is the temporary state of to be, and is the standard grammatical form of the question, especially when referring to people.
Onde você está? Where are you?
Estou chegando! I’m almost there!
Onde estão as meninas? Where are the girls?
Estão no quintal. They’re in the backyard.