accessibility
Readability and plain language
Why does plain language matter, and how is readability measured?
Readability is how easily text can be read and understood; plain language is writing deliberately for that ease - common words, short sentences, active voice, no needless jargon. It isn't dumbing down; it's respecting the reader's time and the fact that stress, distraction, a second language or a cognitive difference all lower the reading level anyone can comfortably handle.
Also known as: readability, plain language, reading level, plain english
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The demo
Type into the box, or load the two versions of the same message below, and watch it score its own readability. Notice how the plain version reads easier - and scores it.
What this demo shows (text version)
An editable text box scores its own readability as you type, using an approximate Flesch reading-ease calculation (based on sentence length and syllables per word). Two buttons load the same message written two ways: a jargon-heavy, long-sentence version that scores as difficult, and a plain-language version - short sentences, common words, active voice - that scores as easy.
The point is that the plain version conveys the same meaning with far less effort, which matters because reading ability varies and drops under stress, distraction, fatigue or in a second language. Plain language is an accessibility win for everyone. Readability scores are a rough smoke alarm, not a grade - they measure sentence and word length, not whether the meaning is genuinely clear; the real test is whether a reader understands it first time.
Write for the lowest reading level that still says what you mean: short sentences, everyday words, active voice, and jargon only when it's defined. Plain language helps everyone - the rushed, the distracted, the non-native, the cognitively-loaded - not just people who struggle to read. Readability formulas give a rough gauge, but the real test is whether someone gets it first time without re-reading.
Swap the jargon-laden version for the plain one and the score jumped from "hard work" to "easy" - same meaning, far less effort. You felt it too: the plain version landed first time, while the dense one made you backtrack. Lower reading level isn't less content; it's less friction between your words and the reader's understanding.
Plain language is an accessibility issue, not just a style preference. Reading ability varies enormously, and it drops further under stress, distraction, fatigue, in a second language, or with dyslexia and other cognitive differences. Dense prose excludes a huge range of people who could understand the idea if it were just put more simply - so plain language widens your audience rather than narrowing your message.
The levers are concrete: shorter sentences, common words over fancy ones, active voice ("we sent your order" not "your order has been dispatched"), one idea per sentence, and jargon defined or dropped. Structure helps too - headings, short paragraphs, lists - because readability is about scanning and understanding, not just word choice.
Readability scores (like Flesch reading ease, used in the demo) are a useful rough gauge, but treat them as a smoke alarm, not a grade. They count sentence and word length, not whether the meaning is actually clear, and they can be gamed by chopping sentences without improving sense. The real test is comprehension: does a real reader get it the first time, without re-reading?