[Cronos]

Russian, like Polish (I know the latter fluently now, the former more like "i can find my way") can be difficult to English speakers who don't know the way declensions work. But if you've learned Latin, then Polish is pretty easy to pick up. Russian is a different ball game due to its insistence on Slavic words rather than imports from Latin or Greek languages, but that's overcome once you know the basic words

Chinese -- from what my sister-in-law (a Japanologist with a passing knowledge of various Chinese dialects/languages) tells me is grammatically very simple -- just the pronunciation can be murder due to the tonal nature of the languages

[Exit148]

With Chinese, it is like learning two languages-— the abc one and the characters. It is one fascinating language, and although I’m not at all
fluent, I’m understood. I do a practice session, and get lost in the etymology of a character. I just love this language!!!!!!!

[Suz in AZ]

Chinese is simple to speak if you are not tone deaf. Difficult to read and write.

Korean is easy to read and write but difficult to speak.

Japanese is difficult in both regards.