One of the better ways to speak English is if the medium of instruction is in the English language. There are pros and cons to this type of education and it all depends on the teacher of the language.
Let us start with the pros first
Learning in a school which uses English as the medium of instruction is almost like immersion. The difference is there is no total immersion. After classes which are taught in English, the student can just go back to the native language and still think in that language. The results can vary. Depending on the teacher and the student, the student can actually sometimes speak the language fluently with an accent and yet fail in writing it or they can read and write if fluently but cannot speak it. If the teacher or professor is the type that demands full attention on the fluency of the language then this can be corrected immediately and hopefully, the results would be reading, writing and speaking the language. However, there is still the barrier of thinking in the language. This is rarely achieved in a school setting.
Now for the cons
English is taught as the medium of instruction in schools whose country may not be fluent in the language itself. These are true in countries in Asia. The subjects are taught in English yet if the teacher cannot or fails to explain the subject properly, they fall back to their native language. They find this really convenient and they think that the method has merits. It may, but the merits are so few that the resulting English spoken would be filled in with the native language and worse, the speaker could not even be understood because of the heavy accent and the need to sound American and fail drastically.
Is there no hope?
The points were just written to make the reader aware that there are advantages and disadvantages to learning the English language in a school setting where the language is taught by those who also cannot speak it well. However, this does not stop the learning to take matters into their own hands and learn through another method, by watching television and learning shows.