Лингвофорум

Those seem easy compared to pshaw and other weirdly-spelled words
I guess they're the hardest because they're often used

1. Phenomenon 2. Anaesthetist 3. Remuneration 4. Statistics 5. Ethnicity 6. Philosophical 7. Provocatively 8. Anonymous 9. Thesaurus 10. Aluminium 11. Regularly 12. February 13. Particularly 14. Hereditary 15. Prioritising 16. Pronunciation 17. Prejudice 18. Facilitate 19. Hospitable 20. Onomatopoeia  / from //lenta.ru,  the list of most difficult words for pronunciation marked by British researchers.

ЦитироватьA manager where I used to work used to say "inVENTory" (a word meaning a stock of something).

If he spoke Egyptian it would be worse...

True, you have to know the pronunciation, but to start putting in invented diacritic symbols would not be authentic English. There are many native speakers of English who mispronounce words for these reasons. A manager where I used to work used to say "inVENTory" (a word meaning a stock of something). I would cringe whenever I heard it, because it should be INvent'ry. The worst thing is that the incorrect pronunciations become standard after some time.

Without dredging up the most outlandish exotica, we can cite such tricky examples as anacoluthon, bergamot, chalazion, hendiadys, and puisne; and the average reader is as like as not to mispronounce cation, emesis, geodesy, patina, presage. In each instance, a single diacritical mark to denote stress or vowel quality would clear up any doubts. English, however, does not exploit such aids to the same extent as other languages.
T_T