Go here http://duolingo.com/#/settings/account and click "quiero aprender inglés" (beside "learning languge").

Thank you, but I don't have the choice "I want to learn English (I know French)?" I have instead : I want to learn Spanish ( I know english) ? I want to German ( I know english) ? I want to learn French ( I know english) ?

You can only learn english if you know spanish right now on duolingo. You will have to wait until they expand this feature to other languages.

i want to learn English (I know Hebrew) do you think it's will be possible?