Who Can Read This?
Readability scores grade sentence length. They cannot see the real failure: a word your reader confidently misreads. A PE partner reads “classifier” as someone who classifies documents and “distributional” as investor payouts - and never knows to distrust either. This tool scores every word against an ambient-English frequency baseline plus a typed audience model, and flags what that specific reader cannot parse or will silently get wrong.
Everything runs in your browser - the passage never leaves it. The algorithms are the reference implementation of isogloss, the audience-legibility library this page demonstrates. An isogloss is the line on a dialect map where one word stops being understood and another takes over; your org chart is full of them.
1 · Pick the target audience
2 · Paste the passage
How the scoring works
Every word is scored on the Zipf scale - the base-10 log of its occurrences per billion words in a large English web corpus (“the” scores 7.6; a term absent from the top 50,000 is rare by definition). Inflections inherit their lemma's commonness, so “classifier's” scores as “classifier”. A term below the audience's rarity threshold (Zipf 3.3) is not automatically a problem - the audience model can still own it.
Common English, or inside the audience's declared vocabulary tiers (a PE partner owns “EBITDA” even though ambient English scores it rare). Kept as-is.
Rare for the audience and not tier-owned: a term of art or coinage. Opaque - but visibly opaque, so a gloss can save it.
The audience confidently misreads the term (“prior” as “prior year”, “significant” as “large”). Frequency cannot see this class - collisions are declared per audience, never inferred from counts. Hover cannot save them either: the reader has no reason to hover a word they think they understand. Substitution is the default treatment.
Treatments follow the channel-routing rules: collisions get substituted (or introduced-then-used when the term must survive), recurring jargon earns a hover-gloss where the surface supports one, incidental jargon gets replaced rather than defined.
When to Use This
Use when
- +Technical work is crossing an audience boundary (memo to the board, model results to the deal team)
- +The reader is senior enough that confusion costs you the meeting, not a follow-up question
- +One of the four presets approximates your reader
Skip when
- -Writing for peers who share your vocabulary - the flags are noise there
- -The problem is structure or argument, not word choice - this scores vocabulary only
- -Your audience diverges hard from every preset; collision lists are per-audience data, and the wrong list gives confident wrong flags
Changelog1 entry · building in publicshow ↓
- First public draft. Client-side port of the isogloss reference algorithms (tokenize / standing / routing / fold-quanta / rephrase prompt) over a shipped top-50k Norvig ambient table; four audience presets; every displayed number pinned to the src/lib/readability model module by vitest fixtures.