My Question is why I can't speak right English when sometime I write very right english
Dear Juweriya, one thing I would recommend is to read as much as you can especially dramas.Dramas are written in dialogues between people.
And don't forget to read out loud because that's the only way to improve your speaking skill.You can pick any kind which interests you.
Reading and writing are complementary to each other. The more you read, the more proficient you will be in writing. :)