As a "wh-" concept, WHERE is the first interrogative we recommend introducing. Many dogs enjoy playing the game "where's X?", in which X can be anything from a toy to another person. As such, it is a concept that serves as an early introduction to the practice of asking and answering questions.
Where is?
"Where"
Model its use while playing the "Where's X" game, choosing different family members or toys for the X.