Descriptive grammar

A descriptive grammar describes how the language is actually used by native speakers; it makes no effort to state what is "correct" or "incorrect" as such concepts would be irrelevant in this context. Such studies are carried out on data obtained through the analysis of a large body of natural language called a corpus.

While useful for the academic study of the language, and for EFL teachers in particular, such grammars are perhaps of little direct use for non-native language learners who may not really interested in a statistical analysis of what native speakers say, but want a prescriptive grammar which gives clear rules about what is acceptable and what is not.

Nevertheless, teachers should be wary of personally accepting as gospel all the simplifications included in coursebooks and would do well to remember that they are exactly that - simplifications to help non-native speakers.