Here are the words in English that are hard to pronounce for English learners.

1) Don't accentuate (=pronounce clearly) the final suffixes and unstressed syllables in long words.
'-ous' (sounds like /es/) various, serious, nervous, obvious, previous, dangerous
'-tion' (sounds like /shin/ not /shon) information, section, decision, population, association, organization, position, commission
'-ture' (sounds like /che/) future, feature, creature, moisture, picture
'-ate' (sounds like /et/ not /eit/) corporate, desperate, private, separate, adequate
'-able' (sounds like /ebl/ not /eible/) questionable, reliable, doable

2) Combinations of vowels e/i/y/u with 'r' in the middle of words - they all sound the same /ɜː/ like in 'girl.
All these words will sound the same: girl, term, turn, burn, spur, Myrtie, shirt, bird, heard, early, thirsty, skirt, fur, dirty, curse, work

3) You need to remember words with silent letters (=letters which are written but not pronounced).
Some of them: (letters in red are not pronounced)
honest, hour, ghost
knife, knot, knee, knitting, knock
autumn, damn, column
bomb, numb, climb, lamb, doubt, plumber, debt
resign, design, foreigner
guest, guess, colleague, guilty, tongue, biscuit
almond, palm, calf, half, talk, walk
write, wrap, wrist, wren, wrong

Make sure you pronounce all these words right. You can check yourself in this audio guide here