Studying English as a Foreign Language (EFL) is not an easy enterprise. English has an enormous number of words--probably more than any other world language--and a variety of irregular spellings and verb conjugations that can be confusing to non-native speakers. It is important to establish certain grammar rules at the beginning of an EFL student's career so he can build upon a strong foundation of English syntax.
Importance of Grammar
Along with weak vocabulary and thick accents, poor grammar is one of the main obstacles that non-native English speakers face when trying to communicate in English-speaking countries. Grammar errors can lead to nonsensical sentences (such as "Me go supermarket") or to comical meanings that are far from what the speaker intends (such as "I must eat the children" instead of "I will eat with the children"). Of course, this happens to English-speakers as well when they try to communicate in languages foreign to them.
How to Improve Your Grammar
The best way to study English grammar is to take a formal course in person or online. An EFL teacher can explain why certain constructions are correct and others are incorrect. She can point out exceptions to rules, give you grammar exercises and mark your work so that you can identify areas in which you are weak.
Another way to improve your English in general is to read as much English as you can. Many EFL students also improve by watching English television, but be warned that not everyone speaking English on TV is speaking correctly!
Common Errors: Irregular Verbs
Unfortunately for beginning students, some of the most common verbs in the English language call for irregular conjugation. For example, we say "I go" in the present tense and "I will go" in the future, but "I went" (not "goed") in the past. And we say "I buy" today and "bring" the goods home, but "I bought" and "brought" yesterday (rather than "buyed" or "bringed").
Common Errors: Verb Tenses
Students whose native tongues do not have "perfect" or "progressive" tenses are often particularly confused by these concepts. They usually need many exercises to learn when to use the simple "I walked," "I walk" or "I will walk" and when to use the perfect ("I had walked," "I will have walked") or progressive ("I was walking," "I am walking," "I will be walking") tenses. Even more confusing is the perfect-progressive ("I will have been walking").
Common Errors: Gender-Neutral Nouns
Many languages assign genders to all nouns, and students who are used to saying "The sun, he is rising" may need to be broken of the habit when speaking in English. They may not have a word for "it" and need to learn what, in English, is considered "he" or "she," (people, boats, specific animals) and what is considered a "thing" (such as inanimate objects or animals in general).
A similar error occurs when students are used to thinking of a word in the plural. For example, students who say "The water are flowing from my sink" may not be considering the fact that in English, "water" is singular.