Hi Brian

Thanks for this essay. It's 270 words, even though it feels shorter for some reason, and the average sentence length is 18 (a little long - try to add more short sentences).

It feels short because although you've given a lot of information, I don't think you've given enough reasons why we should learn other languages.

Introduction

You give some background to the spread of English, and then you switch suddenly into saying that we should learn other languages. This switch or change needs to be marked with an example or a marker word like 'however'. Something like this, perhaps?

Since Great Britain colonized many countries in the 19th century, English has spread and is now the most common second language taught in schools worldwide. However, it does not have to be the only second language. I believe there are good historical, cultural, religious and economic reasons for learning other foreign languages in school.

Paragraph 2

You give three examples (television, internet, science) of English being used worldwide.

Paragraph 3

You have two examples (French spoken in North Africa for historical reasons, Arabic in Islamic countries for religious reasons). It would be good to have a thrid reason to balance the second paragraph.

Conclusion

You have one sentence which summarizes paragraph 2, and gives your opinion.

I see your organization, but I would like more examples in Paragraph 3. I would also like another sentence in the conclusion. This might make your essay longer, but there are a good few sentences we can shorten or tighten up to bring down the word count.

Shorten/Tighten/Various Errors

It can be seen from many channels broadcasting their programmes in English or at least with an English subtitle.

Many television channels broadcast in English or with English subtitles.
 

The dominance of English language not only is obvious in television but also on the other media like the Internet you find that the most contents produced in English (A survey conducted in 2010 by the University of Oxford ).

The dominance of English is obvious not only in television but also in other media such as the Internet, where the majority of websites are in English.
 

In this case, therefore, no wonder to see many countries and individuals tend to choose English as a first foreign language.

It is no wonder, therefore, that many countries and individuals tend to choose English as a first foreign language.
 

However, we cannot ignore of learning different languages in our curriculum.

However, we cannot ignore other languages in our curriculum.
 

There are some countries that other languages have a great influence on their cultures, religions and costumes

"There are" can often be omitted

Other languages have a great influence on the cultures, religions and customs of some countries.

Vague Pronoun Reference

Be careful with pronouns -  see how 'they' is used in the next two examples:

North Africa, for example, because of many years was being France colony, a wide range of French vocabularies is spoken in every day conversations. As they are more adapted with this language, therefore, choosing French is more rational.

In North and West Africa, for example, after years of colonization, French is still widely used, so teaching French as a second language is more rational. 

Here's a second example with a confusing pronoun 'they'

This goes same for other languages such as Arabic that is a holly language for Muslim countries. In fact, they can make a close relationship with their religion.

In this example, there is only one language (Arabic) so we have to change the sentence:

Languages can also be important for religious reasons. As the language of the Qu'ran, Arabic is an important second language in the Islamic world, as Latin used to be for the church in Europe.

Overall, Brian, you have some very good ideas, but you need to give more weight to the third paragraph (the one which has your opinion) by giving more examples. Perhaps some economic reasons for learning Chinese or Japanese?  

A mix of short and long sentences is the best. Having all long or all short sentences makes your writing hard to read. Aim for a mix. Short sentences are particularly good in the topic sentence (the first sentence in a paragraph).

Don't worry about short sentences making your writing look simple. Ernest Hemingway, famous for his short, unfussy style, rewrote the last page of his novel "A Farewell to Arms" thirty-nine times before he was satisfied. He won the Nobel Prize for Literature in 1954. Simple to understand does not mean simple to write.  

The point of writing is to convey a message, not to impress a reader or an examiner. Using short simple sentences can make your message easier to understand.