If you are able to speak English, can you show the same performance in writing,reading and in understanding?

My dear! speaking, writing, reading and understanding are different topics. For example one can fluently speak but cannot write standard letters, essays, articles etc, similarly one can speak without any trouble but cannot read writings of others. some people are very good in drafting letters, writing reports, articles etc but cannot speak fluently. 

we need to focus in writing and learning in school by giving more home work