Hi Brian

Nice short essay on this topic. You have chosen to focus on a particular aspect - languages spoken by very small numbers of people, which is exactly what the question asks.

I wonder however if more specific examples would have made your essay stronger. Are you thinking of Australia? Taiwan? India? Papua New Guinea? Canada? The term aboriginal is fairly specific and often used in a political sense. Only a few people speak Irish or Welsh, but most of them would not want to be called aboriginal. In Australia and Canada there is a move away from the word as well.

• http://www.aboriginalartonline.com/culture/aboriginal.php
• http://rabble.ca/news/rethinking-word-aboriginal
• http://www.whywarriors.com.au/Definitions.php
• http://en.wikipedia.org/wiki/Taiwanese_aborigines

Forgetting about the word aboriginal though, what about other minority languages in danger e.g. in Europe, the Middle East, or other parts of the word?

Simplify/Word Order/Usage

• Some people argue that preserving those languages is wasting time
• Some people argue that preserving those languages is a waste of time
   
• Uniformity in the language may lead to an increase national solidarity
• Uniformity in the language may lead to an increase in national solidarity

This sentence has too many negatives! I had to take two aspirins to get through it.... 🙂

Furthermore, not only preserving aboriginal languages does not lead to less patriotism but also people would feel that they belong to this country and show more respects to the government.

Let's change the word order and remove some negatives. Is this what you mean?

Furthermore, preserving aboriginal languages can help minorities to feel that they belong to a country. They will have more respect for the central government. They will feel more confident and valued knowing that they can pass on their heritage to young generations through stories spoken in their own language.

• preserving and investing money on endangered languages could not be seen as a waste of time
• preserving and investing money on endangered languages should not be seen as a waste of time
    
• Governments could take some measures to keep alive these languages, causing people feel that authorities tend to protect their cultures and identities
• Governments should take measures to keep alive these languages and to help minorities feel that their cultures and identities are protected and respected.

Articles

• In fact, it is a part of cultural identity of a nation.
• In fact, it is a part of the cultural identity of a nation.

You'll notice that I have spent more time on the ideas than on the grammar. That's a good thing! Thanks for all your help with reviewing other writers' work here on the forum.