Everyday when I go to class to teach Structure & Speaking Practice Component, my students ask so many questions. They won't stop until they are totally satisfied with my explanations. Most of the time,answering questions from 20 students at a time is so overwhelming. It's hard to explain when there are so many exceptions and irregularity in English grammar.
SO, that's why I always tell them, "English Grammar is FUNNY!". WHY? They won't accept the irregularity and the weird rules without knowing where do they come from. I just don't want to lecture them on the origin of English language since I learned about it for 2 semesters (equals to almost a year!).
Let me just give you the explanation of English Grammar that I've copied from WIKIPEDIA. Why don't you try to understand about the explanation too and tell me what do you reckon?:
English grammar is the body of rules describing the properties of the English language. A language is such that its elements must be combined according to certain patterns. This article is concerned with (and restricted to) morphology, the building blocks of language; and syntax, the construction of meaningful phrases, clauses and sentences with the use of morphemes and words.
The grammar of any language is commonly approached in two different ways: descriptive, usually based on a systematic analysis of a large text corpus and describing grammatical structures thereupon; and prescriptive, which attempts to use the identified rules of a given language as a tool to govern the linguistic behaviour of speakers (see Descriptive linguistics and Linguistic prescription). Prescriptive grammar further concerns itself with several open disputes in English grammar, often representing changes in usage over time. This article predominantly concerns itself with descriptive grammar.
There are historical, social and regional variations of English. For example, British English and American English have several lexical differences; however, the grammatical differences are not equally conspicuous, and will be mentioned only when appropriate. Further, the many dialects of English have divergences from the grammar described here; they are only cursorily mentioned. This article describes a generalized present-day Standard English, the form of speech found in types of public discourse including broadcasting, education, entertainment, government, and news reporting. Standard English includes both formal and informal speech.