The question whether language X is the most hardest in the world can be quite difficult to answer because the answer differs depending on the learner’s mother tongue. Obviously a native korean speaker is going to have a lot easier time learning japanese compared to the typical english speaker because of similarities between korean and japanese.
But for the most part, japanese is definitely in the running for “the most difficult language in the world”. Foreign Service Institute classifies japanese as a category four(the most difficult category) language for a native english speaker. It should take 2200 hours of study time to become proficient in japanese. For anyone curious: arabic, mandarin and korean are also in category 4. Nobody can say for sure what the most difficult language in the world is. For example, if you challenge the average korean to learn polish and japanese, guess which language he/she will pickup faster. But does that make japanese easier than polish? Not quite. That’s the problem with lists that tries to rank languages based on difficulty. If someone can point to an extensive study where they compare language learners from all over the world in order to try to guesstimate the most difficult language in the world, I’m all ears.
A lot of people no matter what country tend to think their language is uniquely special and difficult for some reason(some weird kind of national pride) but unfortunately japanese people are right in this one. Japanese whether or not is the most difficult language in the world is without doubt among the most difficult languages to learn.
Some people are going to pickup japanese faster than they can pick up spanish or german because they’re strongly interested in japanese or they for some reason have a natural gift for japanese but generally speaking japanese is going to take a lot more sweat and tears to learn than other languages.