This is an important question to think about.  Many learners focus on vocabulary, or grammar, or pronunciation, or other PARTS of the English language. 
 
However, what you really want is total speaking CONFIDENCE.  You want to speak clearly and powerfully.  You want people to understand you and respect you. 
 
You want to feel confident, strong and relaxed every time you speak English.  
 
The problem with most English programs is that they fail to produce speaking confidence.  Their students learn a lot of grammar rules, but they still feel nervous and stressed whenever they speak.