世界中の多くの人と話して英語力を向上させたいって英語でなんて言うの？

There are a variety of ways to express that you want to talk to people in a variety of countries. 'from around the world' is a phrase that implies that there are various people/things from different countries.

When we practise something, it is invariably with a view to improvement, so placing the word 'practise' with the word 'improve' is not really necessary. You express your intention to both practise English and also speak with people from around the world - a dual goal

▪ My vision is to improve my English by speaking to people from around the world in English. This is telling someone that your plan is to speak better English and that you think speaking to people from around the world will help ▪ Speaking English to other people will improve my English a lot. This is saying directly that the way you want to improve your English is by speaking more to other people.

If you want to speak to different people around the world to improve your English then you could say 'I want to speak to different people from around the world to improve my English' You can also use the term 'Nationalities' which means people from different countries (french/spanish/italian etc)

You could also say 'I want to better my English' 'I'm aiming to advance my English' Other words you could consider might be Help, develop, upgrade, promote, or progress If you just say 'English', people will assume you mean the language in this context. But you could be absolutely clear by saying 'I'd like to enhance my English language skills' 'Around the world' could be replaced by 'worldwide' or by 'from around the globe'

Because there are two clauses in this statement, you can say "I want to improve my English" or "I want to talk with people around the world" first and it will still make sense. In the last example sentence, I used the word 'communicate' which is a similar word to 'speak' and 'talk' and also means to have a conversation with somebody.

English is spoken by more non-native English speakers than any other language. Therefore it's a good idea to practise speaking with native and non-native English speakers to improve speaking and listening skills. There are lots of ways to express your opinion on this. One example would be to say "Speaking with English speakers from around the world will help improve my English skills".