Grammar is learned unconsciously at a young age. Ask any five year old, and he will tell you that"I eat" and"you eat," but his dog eats." But a human's syntactical knowledge goes farther than what is grammatical and what is not. It also accounts for ambiguity, in which a sentence could have two meanings, and enables us to determine grammatical relationships such as subject and direct object. Although we may not consciously be able to define the terms, we unconsciously know how to use them in sentences