[ff7c11]

French speakers often struggle with beach/bitch :)

[alfonsodev]

As Spanish speaker I struggled myself with that one, sweating, and probably over correcting making the e super long beeeeach to be safe. :D

[desert_boi]

In German, the vowels between schwül and schwul were really difficult to do for me as an American English speaker. I couldn't ever hear the difference between rounded and unrounded vowels. American English vowels are only rounded in the back. u and o (and in the East the au in caught).

[pmontra]

Italian speaker: also piece / peace / piss and sheet / shit.

We have only seven vowel sounds. A i u and open / closed e o. But different parts of the country often use only one of the two e and o sounds.

[blowski]

There's also the classic can't, count, and cunt (the last being one of the most offensive expletives).

[dvirsky]

For me that actually was easier - learning English mostly from TV as a kid I just pronounced can't as "kent".