I'm newly here, and I’m trying to use the community gradually... so please be cue.
I would like to know which is the best English, accent and slang talking, to learn proficiently.
My choices would be between American, English of the United Kingdom or also Australian English.
I know that this could be subjective, feel free to say which one for you and why :)
It doesn't matter.
It doesn't matter which, you will be understood in any English speaking country if you learn any of them. Personally I would try and expose myself to different variants and accents of spoken English, I think it would be more beneficial than just restricting yourself to one kind. Personally I think people get too hung up on this, English has enormous variety in accents and for me there is no one 'best' kind.
Agree, the accent doesn't matter. Plus if the English is not your first language, your English accent will be influenced by your mother tong, anyway. As long as your pronunciation is clear and people can understand you and you understand them... Grammer and vocabulary are the most important.
American. Think of all the American films, popular worldwide.
It's been said the Mid-eastern American accent is the most pleasant. But it's really a matter of opinion.
Neither slang nor accents are a significant issue.
To learn a language proficiently, you can do something as simple as write a single sentence in a notebook, and afterward, write several more sentences and then vary them slightly.
It helps to use the Dolch Lists for the most 100 common English Verbs and Nouns
and to use these in many sentences with variation.
Word associations between Synonyms and Antonyms can be of great benefit.
A language practice partner can be very helpful, but it has to be an activity that is something other than Finding----A---Friend. A "friend" may have no knowledge at all about how to advance in a language study.