[Aengeuad]

Those are some of the hardest languages to learn but that's only really true for a monolingual English speaker.

When it comes to how difficult a language is to learn it depends greatly on what languages you already know and how distantly related (if at all) the new language you want to learn is from a language you already speak, shared language features or phonology or vocabulary also help out as well, etc.

For example while Polish may be difficult for an English speaker it does share some mutual intelligibility with Slovak and Czech, likewise with Finnish and Estonian. Chinese and Japanese are two very different languages but Japanese makes extensive use of Kanji/Hanzi, being fluent in one of these will help you understand the written language of the other faster and knowing either will give you a significant leg up in learning the other over somebody who only speaks English.