This isn't really a direct answer to the question, so I apologize for that. I hope it helps your understanding, though...
German and English aren't mutually intelligible, reading or listening-wise. Neither are French and English. English gets a large portion of its vocabulary from French and Latin, and French also gets a large amount of its vocabulary from Latin. This means that someone who can read English can likely recognize many of the words in written French, but not really enough to understand it.
For German, English shares a lot of vocabulary, as well, but what makes these languages "closely related" is that they are both in the "Germanic Language Family". They have a recent common linguistic ancestor. Essentially, while English and German may not have a large vocabulary overlap, sentence structure and grammar are similar and historically indicate a recent common language that they both diverged from. An English speaker can possibly understand written German, but it takes a lot of effort and understanding of the changes that occurred in the two languages as they diverged from each other.
Last thing I'll say is that the vocabulary that English barrowed from French and Latin (which makes up the majority of English vocabulary) isn't evenly distributed among "genres" or frequency of use. More "fancy" words are likely French or Latin in origin (think science terms and other jargon), while common words are mostly Germanic in origin (think words like "and", "the", pronouns, etc.)
Ease of pronunciation depends on how similar the sounds are between ones native language and the language one is trying to learn. For a native English speaker, Japanese has much more in common sound-wise with English than Korean does, so it would be easier for the English speaker to distinguish the important sounds of the language.
Another commenter mentioned with more exposure it becomes easier to pronounce the language, which is true for any language, but if your question is about ease of pronunciation, then the language that requires less exposure to get would be the one that's easier, and I think that's Japanese.