If you are not able to speak, then it is one of the reasons that your word power may be weak. If you make your word power strong, framing sentences will be very easy. If your word power is weak, then it also causes you to be more hesitant because you may not be correctly speaking.
You should learn at least a few words a day to improve your English. You should read books, news, online news, etc., and see their meaning and pronunciation. It also helps you boost your confidence.
References
Jargon
Vocabulary, Strong words, Power words, Formula, Framework, Post, Pronunciation