I saw a few comments regarding the difficulty of languages within Category V. Particularly Japanese/Chinese.

I speak Mandarin Chinese and Japanese on a near daily basis, and definitely consider Japanese to be more difficult than Chinese. Nowadays Chinese everyday, previously Japanese everyday. I find both languages and cultures to be very fun and will point out some of the key differences that I think make Chinese easier than Japanese. I also encourage anyone to jump in either of the languages and have fun. It has been life changing for me. :)

- Chinese grammar is far simpler (less fluff) and somewhat maps to similar word ordering as English. Japanese also has lots of fluff and rigid rules for grammar, and the word ordering/sentence structures are much more alien than Chinese to an English speaker.
For example, English: "I will go to the store", Chinese: "I go store", Japanese: "I SUBJECT_MARKER store DIRECTION_MARKER go". (fun fact, Japanese grammar is not actually backwards as people often say, it's more like a bubble of nested clauses, can elaborate more if anyone cares.)

- Chinese verbs/adjectives for example, don't conjugate, you just add a few context words. Japanese, while logical, still has more conjugation rules/exceptions (though not near as awful as English)
For example, English: "I was a Marine", Chinese: "I before is Marine", Japanese: "I SM Marine was".

- Japanese formalities are far more deep/complicated than Chinese. Yes, Chinese has formalities, but anyone who has done serious deep dives in Japanese business / honorifics will understand.

- Chinese while written has a high barrier to entry because it's all characters, they at least with very very few exceptions, all have only one reading. This makes memorizing them much easier than Japanese. In Japanese, you have two forms of reading (onyomi & kunyomi), you can think of it as the Chinese & Japanese readings. Most characters have at least 2 readings, and some even more. This makes memorizing them more complicated.

- Chinese characters are simplified, thus easier to write.

- Japanese in addition to Kanji (Chinese characters), also has 2 phonetic systems, katakana (for foreign/loan words), hiragana (Japanese words). And hiragana gets mixed in with kanji (loosely as the conjugated part of verbs and other grammar). A new learner of Japanese would be excited to learn hiragana, only to find out, no one writes in all hiragana (which would be awful to read). So, they end up not being able to really read much, until they start learning lots of kanji. So the phonetic systems only really help when you are writing and forget a kanji. But honestly, you'll find that you just type both languages 99% of the time so it doesn't matter as much. Except that I type Chinese much faster since words are literally just shorter.

- The hard parts of Chinese are the tones. Japanese pronunciation is by far easier. Cantonese pronunciation is harder than Mandarin as there are also more tones. (to me at least)

- Both China and Japan have deep histories and cultures, which finds themselves at the heart of both languages. Both will take many many years to sink in and feel comfortable.

- Another cultural item but I find Japanese people much more willing to speak to foreigners in Japanese, and have patience with bad Japanese. Chinese people are much more direct and likely to laugh at your Chinese pronunciation or make fun of your speaking early on, or even just never speak to you in Chinese and prefer to use English. This happens in both cultures, and the better you get the more likely both countries will be willing to speak in their native languages with you, so just push through it, and don't take it personal. When you're abroad, they'll be much more likely to speak their native language with you since most people abroad won't be able to speak very proficient English. Which is one of many reasons why studying abroad can be hugely helpful to learning the language. I also recommend to just be conscious of whether or not that native wants to use speak with you. Some people try and force it.

I have also studied Korean and put it on par with Japanese, and thankfully because I know Chinese/Japanese characters, I can more easily remember/guess many Korean words which are actually rooted in Chinese. I feel bad for people trying to brute force memorize hangul words (or any alphabet to be honest)