hum..I really must brush up on my linguistics courses at University... . If I rememeber well, 'descriptive grammar' basically refers to how people talk (grammar in use) whereas 'prescriptive grammar' has to do with how people should talk (grammar usage).
Basically, something like this...
I look forward to the right answer!
linguistics 
. If I rememeber well, 'descriptive grammar' basically refers to how people talk (grammar in use) whereas 'prescriptive grammar' has to do with how people should talk (grammar usage).
Linear Mode
