Try reading any novel written by Joseph Conrad.
Born Polish, he learned to read and write English far better than most native speakers.
Though a little old fashioned now, his language is still clear and brilliant.
Contemporary novels frequently use the latest idioms and slang. I myself find this frustrating because I'm 68 and don't understand most of it.
I far prefer novels that use classic language that bears the test of time. These can often use idiom in the speech of characters to add realism (verisimilitude), but the context makes the meaning clear. Charles Dickens is the exemplar.
Alternatively, try dipping into many books in a library, or sampling first chapters online.
You'll eventually find writers whose style matches your well developed English.
I'd be curious to know what you're reading now.
What are some example of the strange words, or "sentences" in a strange order?
