Firstly, I would like to commend you on your knowledge of written language considering it is not you first language. Well done!
I originally edited your essay before but the webpage expired and everthing was wiped, bugger!
Here are some of my opinions:
You introduction sentence is stating your thesis but it is not justified. Perhaps try using a different connective instead of as well use in addition or addtionally. See my example below:
Learning a second language enhances communication between people because communicating acts as a tool to extend an individuals language dialogue. In addition, speaking a second language excludes misunderstanding between cultures and societies as all language involves diversity in cultural contexts.
I don’t really get the second paragraph below so I made a few edits including connecting information with previous paragraph. Have you considered using references to support your statements? Also, it is not wise to start a sentence with because. Remember this is only my opinion.
This diversity of cultural contexts and need (by who) for effective communication increases the importance for individuals to learn and speak a second language. In historic times, the world was known (by whom?) as a small village and the neccessity to aquire an additional language was not a prority. The role that communication plays in the modern world strengthens this need……..
Next paragraph, try using a different connective instead of in fact perhaps go back to your thesis
Another interesting aspect of learning a second language is understanding other cultures. This can result in preventing confrontation between cultures and societies because that common knowledge of respect and understanding is ……..
Sorry, I have run out of time. Hope some of this helps you with your essay. Some hints, spell check manually and through computer. Read aloud and work on your connectives. Try and think of some more complex connectives instead of ‘also’ and ‘the last idea.’
(I am a student teacher so I am still learning)