This is one of a perhaps infinite number of posts differentiating grammar from syntax.  Our understanding of the two words is evolving.  Grammar is a floppy term endowed with many meanings, depending on who is speaking, and in what context.  It is the broader of the two terms, grammar and syntax.

Grammar has traditionally been considered the study of the rules of language usage. These rules ranged from “the subject must agree with the verb” to “don’t split an infinitive.”  This method of studying language is called “prescriptive,” which tells how we ought to talk.  Its companion method is called “descriptive,” which studies how we do talk.

The descriptive approach has won out for two reasons, the first of which is that some of the prescriptive rules are widely ignored. The form “There is a lot of reasons,” where the verb does not agree with the complement, has become common even among television announcers other linguistic authorities.  Even highly educated English speakers might use the word “ain’t” from time to time.

The second reason is that language is constantly changing, even in its grammar.  A previous post predicted that “Me and Mary are going to to the mall” will some day be considered correct. After all, we jettisoned “thee” and “thou,” and proper American pronunciation has changed from Franklin Delano Roosevelt’s British tilt to Jimmy Carter, Bill Clinton, and George Bush’s southern inclination. There is no way to either control or predict change in the basic practices of our language, so most linguists watch it all happen and make their pronouncements later.

There is, of course, a standard language, and all students should be taught to use it; but the standards are changing, and we should be aware of them and discuss them logically, not as if we had been stabbed in the heart, when a student says “There’s a lot of reasons why I wasn’t here on Monday.”