How can I learn the english language in three months or lets say four months ?
How can I teach children the english language in a simple way?
How can someone teach the adults the english language in a simple way and a short time ?

How can I evaluate the students performance in learning english ?

That's a tall order to both learn it quick - and learn in well enough to teach others.

Start with mastering it yourself and go from there.

Here are a couple resources you might find helpful:

http://www.eslgold.com/
http://www.eslmonkeys.com/

Thanks for your help I really appretiate it .

How can I learn the english language in three months or lets say four months ?

To learn the English Language properly
Would take the average person over 10 years.
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How can I teach children the english language in a simple way?

There is NO simple way to teach children the
English Language.
The best way is to send them to England
And let them live their first ten years with an English family.

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How can someone teach the adults the english language in a simple way and a short time ?

There is NO way of teaching adults the English Language easily and quickly.

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How can I evaluate the students performance in learning english ?

The best way to evaluate the students performance in speaking good English is when they freely admit to you that they are actually
Thinking in English and NOT translate from their first language.

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