Whatt is happening with my English study? (mixed English)

I have been studying English for more than nine years now. Yet when I try to read the books in English, I still find it was very difficult, especially certain advanced-level books and papers.
Worse, my English is a mixure: British English accent but with American words and phrases. Really weird!

Note: for general comments - ie. when you read books on occasion - use present simple. I suspect this is not a past-and-finished issue, but an ongoing problem.

If it is an ongoing problem, then use: What is happening with my English study?
If it's a new problem which changes things, then use: What is happening to my English study?

Objectively speaking, both the British accent and the American accents sound beautiful. Although the former suits my voice, for most people think the British accent sounds more stiff and short, while the American accent sounds more soft and round. To some extent, the American accent is more difficult for us to imitate I think, due to the retroflex consonant.

I'm not sure exactly what you mean by that last sentence: do you mean learners in general or Chinese native speakers? Also, are you referring to one style of the American R (which is not exactly retroflex) or the retroflex used in Mandarin?

I'm sure others have the same problem as me.

When someone has a problem with you, it means you and that person have an ongoing disagreement.

Whatt happens to my English study?- mix English

I have been studiying English more than nine years.But when I tried to read the English books, I still found it was very difficult, especially some professional books and papers.
And my English is a mixure—— British English accent and American words and phrases. Really weird!

Objectively spkeaking, British accent and American accent both sound beautiful. Just because the former suit my voice, for most people think Birtish aceent sounds more stiff and short; while American accent sounds more soft and round.And in some extence, American accent is more difficult for us to imitate, I think, ig  retroflex consonant.

I'm sure others have the same problem with me.