Traditional grammar is usually based on earlier grammars of Latin or Greek and applied to some other languages, often inappropriately. For example, some grammarians stated that English had six cases because Latin had six cases. Traditional grammar emphasizes such matters as correctness, linguistic purism, literally excellence, the use of Latin models and the priority of the written language. Although there has been a trend towards using grammars which incorporate more modern approaches to language descriptions and language teaching, some schools still use traditional grammars.

Modern linguistics differs from traditional grammar at least in three basic ways. First, linguistics describes language and does not lay down rules of correctness. Linguists are interested in what is said, not what they think ought to be said. So they are often said to be descriptive, not prescriptive. A second important way in which linguistics differs from traditional grammar is that linguists regard the spoken language as primacy, not the written. It is believed that speech came into being first for any human language and the writing system came along much later. Thirdly, traditional grammar is based on Latin and it tries to impose the Latin categories and structures on other languages, while modern linguistics describes each language on its own merits.