I'm currently trying to translate a speech E-J, and I'm aware I could get things wrong if I don't understand the nuances of Japanese words - which, put simply, I don't. My level is very basic, and I'm writing a speech at a level higher than I can presently do with just my own resources. I can probably find my way around dictionaries, but one thing I don't know how to do without keeping a Japanese translator on hand, or posting a question to JSE or /r/LearnJapanese every ten minutes, is learning the nuances between words. Is there any resource suited for this purpose?
The best response I could give is to use the resources at Resources for learning Japanese: thesauruses tend to help with differentiating between similar words, dictionaries for getting the general definition, and corpora for hypothesizing whether it's correct to use words and phrases etc in a certain way.
I often use Space ALC for figuring out the general gist of how words are used, and Weblio for the thesaurus, English/Japanese dictionary and native Japanese 大辞林 dictionary (native dictionaries tending to be a more accurate indicator of nuance than bilingual) among other resources, but different people will have different preferences.
Even if you do draft it yourself, I strongly recommend having a native speaker check over your speech to fix mistakes and unnatural phrasing if possible.