Me  too, Stella.

My speaking skill makes me headache but i think the only way to improve your speaking skill is: you don't worry and not afraid wrong to say. you need to practice a lot with native speakers english to learn their intonation when they speak and their pronunciation.

Of course, if you're lucky you will meet the native people are very enthusiastic and patience to correct for you

I hope you understand what i'm saying. My english is not really good.

Good luck

What you describe is very common, and I recommend following <a ui-sref="user({id:comment.commenter_obj.id})" href="https://www.italki.com/user/2716191">Andres</a>' advice [above], and note that it is not only vocabulary that you need to acquire, but also to use verbs in the correct tense, etc.,  and how to construct sentences.  There is a great deal of 'laying the foundations' before you can start to build your house.

As <a ui-sref="user({id:comment.commenter_obj.id})" href="https://www.italki.com/user/3136751">AnhThuy</a> says [above],  you should try to become familiar with pronunciation and intonation.  This is best done, not by trying to speak, but by listening carefully and, if necessary, listening to the same passage several times, or even many times.  Listen as much as possible to broadcasts in English, on the radio or TV, or find some material on the internet.

When your foundations have been laid and you feel more confident, that is the time to try to converse with a partner.  Try to find a partner who speaks in the same accent that you have become familiar with through listening.

hi, stella! i could understand you, although i never feel nervous, but sometimes i feel speechless. I felt that even though i could communicate with other people using their languages, but our topic is always simple. 

i thought the most important is words, which could be a limitation of expression. then you need courage to step in.