Some posit that Groot's language is not limited, but is instead extremely subtle, and the tiny variances of inflection and posture convey whole libraries of information. Of course, the leading proponent of that theory is Maximus the Mad, so it's best taken with a grain of salt.

Groot nods again, rooty feet nudging the sand around a bit. Pointing over in the direction of the grills, he asks, "I am Groot?"