Hi, I am not a native speaker but thanks to your question that invokes me to write something in response. 

Nowadays, English has become a very dominant language that motivates many and more young generation  to engage themselves to English learning without too much thoughtful consideration about their primary language which is highly associated with their culture and heritage. I strongly believe a language can not only be a communicative tool but also it may represent human intelligence, culture, or even to spiritual level so that we should not give up rescuing these endangered languages even we still encourage people to learn English.

 First of all, there is no denying it would be very convenient to communicate on a basis of one language in the world for people who would like to travel, study, or work.  However, the assumption is worthy to ponder if there is only one language on Earth that we will pay for the one-language world. Certainly, we will lose lots of human treasures built up on a basis of languages that include culture, heritage, concept, arts, drama, music.....etc. It is a matter of balance between gain and loss so we have to measure if it is worthy to take it.  

Aside from that, for sake of new devices developed in recent yeas, non-English speakers can look forward to a hopeful invention to communicate with English speakers through a device as small as a smart phone when they speak to someone who is speaking different language. Think about how many people could image nowadays written English can be easily translated to another language without too much difficulty by way of Google translation? In case of that, can we expect there will be new technology hitting the market before long to help us understand what other language speakers are speaking and interpret instantly while we are speaking and listening?

 Remember what we have been taught to have elegant handwriting in the elementary school shortly before computer writing has been well developed? At modern society, the teaching in the school has been shifted drastically from rote learning and harsh  handwriting to practical retrieval of information on internet to solve problems in the real world. Do you not consider we spent too much time on useless handwriting before? That appears to indicate maybe today's give-up is tomorrow's regret. Think about the number of languages in the world has dropped to a handful, how can we expect culture showing up in the world can be vivid and colorful which is supposed to be the root of creativity.

 In general, even that is pretty hard for these linguistics researchers to rescue these endangered languages in mostly remote areas, but they are doing the right thing to nurture our offspring, inspire humane spirit and give us brighter future. 

Essay

The first and the most significant reason is that the diversity of languages, shows the uniqueness of the world. If a language becomes extinct, the culture, literature and civilization behind it would die out too. The majority of traditional myths are written in minority languages. The variety of languages shows the richness of world civilizations and they should be passed to the next generation. Moreover, unpopular languages introduce their own culture and history and gives them a unique identity that other people can learn about.

However, some people think the disappearance of languages can not be prevented because of globalisation, for instance, when most of the people use international languages such as English, French or Spanish, it is not a threat for society and this helps people to interact better and easier and reduce the culture and language barriers we have in our world. As a result we have a better understanding among nations.

To sum up, each language represents the identity of a community. In my opinion these languages should be preserved in our world.

Hello Ghasal,

Interesting essay, I just completed a short course on linguistics which included a section on language extinction and all of the points you raised came up on the course.

Some small spelling mistakes and some problems with articles and correct use of words (noun forms) but apart from that it was quite good.

Bob