Which is more important - communication or correct English grammar?

One question English students often ask is: Which is more important - grammar or communication? For spoken English, the simple answer is that, on the whole, communicating is more important than correct grammar. After all, the main goal of speaking English is to communicate ideas, not just to avoid making grammar mistakes. However, this certainly does not mean that grammatical accuracy is not important. In fact, whether or not a student can communicate sometimes depends on whether they get their grammar right.

All languages use grammar to some degree as a way to convey meaning, but some languages rely on grammar more than others. English is one language in which grammar makes a big difference in meaning. Consider, for example, the two following sentences:
1) I like dogs.
2) I like dog.

Both of these sentences are grammatically correct, but the meaning of the two sentences is quite different. Sentence #1 means "I like the kind of animal called dogs." (When countable nouns are referred to in general, the plural form should be used.) On the other hand, sentence #2 means "I like dog meat." (The singular form of some countable nouns may be used as mass nouns, and for many animals - such as chicken, turkey, snake, or even monkey - this means their meat.) Even though there is only one small grammatical difference between these two sentences, it makes a big difference in meaning.

Mistakes in grammar do not always result in communication problems, and English speakers are often able to understand sentences that have grammatical errors. However, grammar mistakes can sometimes make a sentence difficult to understand, or may change its meaning completely, so this is one reason why students should try to be as grammatically accurate as possible.

A second reason grammatical accuracy is important is that poor grammar may give people the impression that students aren't very smart. To a large extent, people judge how intelligent other people are by how well they speak and use language. Students who make many serious grammar errors simply don't sound as intelligent as students whose English is more accurate.

Of course, students don't need to worry too much about making grammar errors; English speakers know that it is not easy to learn English, and they generally don't have a bad impression of a student just because he/she makes a few grammar mistakes. However, if students want to be taken seriously and respected by English speakers, it helps if their English is as accurate as possible.

Word and phrase list:
on the whole: in general. Ex: There are some parts of this book that are boring, but on the whole it is quite interesting.
to convey: to communicate, to carry. Ex: He didn't say that he was happy, but the smile on his face conveyed his joy.
to result in: to cause, to make something happen. Ex: Her long hours of English study resulted in good test scores.
to give the impression that: to cause (someone) to think that something is true. Ex: The bored look on his face gave me the impression that he didn't like the movie.
to judge (A) by (B): to use B as a way to decide whether or not A is good. Ex: You can't always judge a book by its cover.
to be taken seriously: to be respected and paid attention to. Ex: If you want your employer to take you seriously, you will have to work harder.

By: Don Snow, Learning English: A Textbook for English Teachers