How to be composed and clearly talk about what's on your mind?

I’m the same way. Probably the simplest way to overcome expressing yourself in public would be to practice public speaking.

If I recall correctly, Toastmasters helps members improve communication skills. Might be worth checking out.

I have the same problem – Most of the time, I feel I express myself well through written word. Of course, there’s always danger when using slang or jargon, but for the most part, I do well. However, I have a very hard time expressing my thought in words, because it seems that I attempt to speak as quickly as I’m thinking. But of course, thoughts run in tangents, and since the person I’m speaking to can’t hear my brain, they’re just getting snippets of the entire mental conversation. That, of course, makes little sense to anyone.

Do I have advice for you? No. Unfortunately, I’ve just avoided speaking up around people. It’s particularly hard because I have a job that requires me to speak to people on the phone all the time, and know stuff to boot. I hope I’m getting better at it. And I get my thoughts out in writing whenever possible.

It’s a form of social anxiety. Pretty minor, although if something were to happen, it could blow up big. You could see a therapist to work on it. Or you could practice in person. Find someone to meet with to practice English conversation. Do it regularly. You will get used to this person over time, and this will help you with people you don’t know, as well. You just need to develop confidence and that comes through practice. You need to control your practice sessions, and you should find a conversation partner to work with.

@burntbonez I don’t know where to find a conversation partner, could you recommend someone?

If there’s a bulletin board in your area, especially at a university, I think people often put up notices for conversation partners in various languages. Or just ask your friends if they know of anyone who might be willing to do it. You have to network.

I also think this is a good idea.

Also, if there is a university, you might check with language departments and ask if they have lists of people who are willing to engage in conversation with foreigners.

A lot of people are far more articulate when writing as opposed to speaking or talking. Some of it is social anxiety, in that we feel the pressure to communicate at a certain speed when people are listening in real time.

Get involved in a debating team, explain your purpose of being there, you will find most people are willing to help and steer you back on track. As well as give guns when necessary.