More than one of my beta readers feels a certain WIP of mine has too many words that need looking up. Much as I'd like to assume they just have unusually small vocabularies, it's more likely I've overestimated the average reader. Ideally I'd copy-paste the whole thing into this, which highlights any word not in English's most common thousand, but since 8-year-olds average a 10,000-word vocabulary I think that's too restrictive, especially since my intended readership is adult. Is there a similar option with a larger whitelist? Or if I shortlist possibly obscure words for reconsideration, is there a way to tell how well a word is known?
The former analyses and estimates the general 'readability of a passage of text using the Flesch-Kincaid Reading Ease, Gunning Fog Index, Kincaide Grade Level, SMOG formula and Dale–Chall Score and Fry Reading Graph metrics. The Analyzer works best with plain text.'
The latter 'can be used to explore vocabulary. It identifies rare words, and long polysyllabic words with more than three syllables which may be harder for an audience to understand. The Difficult and Extraneous Word finder also finds extraneous words, such as adverbs and double hedge words which may make a sentence needlessly longer.'
Hope this helps.