The document discusses what grammar is and its importance in language learning. It defines grammar as the rules that determine how sentences are formed in a language, describing the structure and combination of words. Morphology covers word formation rules, while syntax covers word order rules. The document also presents arguments from experts on both sides of whether grammar should be explicitly taught, or learned implicitly through communication. Some say it helps with accuracy and prevents fossilization, while others argue it is not necessary for children learning their first language.