This graph to me says its just another one of those shitty things that goes viral on reddit and the people who made this graphic they do not really know or speak the langauges. Japanese is very easy to speak, there is also so much material out there from movies to tv documentary, from chats, to Japan tv shows. It would be easy to speak Japanese in a neutral way but to sound like a native and use honorifics, how to talk down to others, talk up to others, when to address people by their title and again you have regional dialects, the Osaka-Ben OOookini comapred to the typical arigato from a store keeper in Tokyo.

I would find Chinese a little more difficult to Japanese speaking, the dialects in China feel and sound and structure totally different to each other, Mandarin, Wu (Shanghainese), Gan, Xiang, Min, Hakka, and Yue and not to mention the overseas diaspora and ex-Pats and the fact Cantonese from Guangzhou (Canton) seems like a totally seperate langauge and sounds more like maybe Thai or Vietnamese, simplified Chinese might be the easier to read but Japanese with its 4 alpabets would be close to the level of reading and writing difficulty, Cantonese seems far more complex as a langauge to write using the old style of Hanzi or kanji. Arabic to me is disgusting, i HATE the sound of it the moaning, hacking, groan, cough hack noises, i guess me regional variations are less worse than others, I would also HATE islam I read some of that Koran or Quran and seen the founder of that shit religion was something like a cross between pedo Epstein and the terrorist bin Laden, maybe its just psychoacoustics why some person just hates say the tones inside a trumpet or a banjo or some instrument and they can't explain why they don't like the instrument. I don't really have anything against the people, Arab atheist are fine, or ex muslims who coverted to another religion but I have little time for the langauge or culture, it would be almost impossible for me to learn Arabic simple reason for me because it tells me its a language of decacy and death, it was once a garden of learning and open ideas and I hate what the region has become over time, I hate Arabic it disgusts me and I can never learn it.

European languages are probably easy once you start another because they will have some Nordic roots or Salvic Balkan or common Latin root which will help one go into another language to learn, i guess the trick here is not to mix them up and again local dialects with each European language.