What is traditional prescriptive grammar?
Keeping this in view, what is meant by prescriptive grammar?
A prescriptive grammar is a set of rules about language based on how people think language should be used. It can be compared with a descriptive grammar, which is a set of rules based on how language is actually used. A prescriptive grammar would reject 'He goes', meaning 'He said', as incorrect language.
Simply so, what is the difference between descriptive and prescriptive grammar?
The main difference between descriptive and prescriptive grammar is that the descriptive grammar describes how the language is used whereas the prescriptive grammar explains how the language should be used by the speakers.
I'd argue that prescriptive grammar is important to teach so that English language learners can make the effort to use standard English when other variations are not suitable. English language learners should understand this. Our job as teachers is not just to teach correct English but also appropriate English.