Writing clearly: the part of accessibility no tool finds

Contrast can be measured. Alternative texts can be counted. Whether your text is understood, no checking tool finds out — and yet it is the barrier that affects the most people.

It affects people with learning difficulties and cognitive impairments. It affects everyone for whom German is not their first language. It affects older readers, tired readers, hurried readers. And it affects everyone who wants to look something up quickly on the phone on the train.

The pleasant part: this is the only area of accessibility where the work shows up directly in enquiries.

How people actually read on the web

Namely, at first not at all. Reading on screen happens in three phases:

Skimming. The text is scanned quickly for keywords to grasp the main message without reading every word. Whatever sticks — ideally terms highlighted in bold — becomes the anchor for the next phase.

Scanning. Around the anchors found, fragments are read and checked for relevance.

Reading. Only when something seems to fit is it actually read.

That means: your headings, your highlighted terms and the first words of your paragraphs do the real work. The running text in between is only read if these signals have convinced.

Remarkably: screen reader users work the same way. They do not listen to the page, they jump from heading to heading, check, and enter where it fits. The structure that helps the skimmer is the same one that helps the blind user.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.1)

Why simple does not look stupid

The most common worry on this topic, especially among trade businesses and consultants: “If I write too simply, I look unqualified.”

Research says the opposite. Studies on language processing show that authors are perceived as more intelligent when they use simple words. Competence does not show in producing complicated texts, but in conveying complex matters understandably.

There is even a connection with the typeface: a hard-to-read typeface leads to a more negative assessment of the author's intelligence. The reader attributes their own effort to the writer.

The reason lies in how the brain works. A text that is easy to process creates a feeling of familiarity and agreement. A text that costs effort creates mistrust — even when the content is the same.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.2)

The Hamburg comprehensibility model

The most useful tool for your own text work is over fifty years old and comes from three psychologists at the University of Hamburg. It names four features by which comprehensibility can be pinned down:

1. Simplicity. Common, concrete, vivid words. Explain unusual expressions and abbreviations. Short sentences. Few or no foreign words.

2. Structure and order. Name the topic clearly at the start. Order the points sensibly. Make the relationships between statements visible — through paragraphs, subheadings, highlighting, summaries.

3. Brevity and conciseness. Only what is necessary for understanding. Leave out side information. Do not overload. A certain amount of repetition is fine, it helps understanding.

4. Stimulating additions. Images, graphics, narrative elements that bring the text to life and spark interest — without covering up the essentials.

Together the four are a better yardstick than any counting rule, because they can be applied to a concrete text without having to calculate anything.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.2)

The concrete rules

From WCAG technique G153 and practice, in the order of their effect:

One topic per paragraph. The single most effective move. A paragraph that deals with three things is found in none of the three phases.

Sentences of 15 to 20 words. That is the common recommendation, and it works. Split longer sentences into two or three.

Important here: it is not about every sentence being short. A text of nothing but eight-word sentences becomes staccato and tires the reader too. It is about the average, and about having no sentences longer than three lines.

No jargon without explanation. And: as few technical terms as possible. If a term is necessary, explain it the first time it occurs.

Spell out abbreviations. Give the full form the first time: “16 GB working memory (RAM)”. That is better than the technical markup through the <abbr> element, because the spelled-out form then helps all readers and not only those who hover over it with the mouse.

Replace long words with short ones. In German, “genehmigen” becomes “erlauben” (approve becomes allow). “Öffentlicher Personennahverkehr” becomes “Bus und Bahn” (local public transport becomes bus and train).

Cut superfluous words. Everything that does not change the meaning can go.

Lists instead of enumerations in a sentence. A sentence with five points separated by commas becomes a list with five items. Immediately easier to skim.

Use terms consistently. Not alternately “check”, “audit” and “analysis” for the same thing. That goes against everything you learned at school about repeating words — but in a technical text consistency matters more than variety. For search engines and AI systems too.

No idioms and metaphors. “Das steht auf einem anderen Blatt” (that is a different matter), “das Kind mit dem Bade ausschütten” (throw the baby out with the bathwater) — they presuppose cultural knowledge. People with cognitive impairments or learning difficulties may take them literally, and for people who speak German as a second language they are simply incomprehensible. If you use a metaphor, explain it.

Active instead of passive. “We check your website” instead of “Your website will be checked”. Shorter, clearer, and you learn who is acting.

Address the reader. “You can sign up” instead of “Registration is possible”.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.2)

The readability index

There are formulas that calculate readability from sentence length and number of syllables. The best known is the Flesch index, adapted for German by Toni Amstad — German words are longer than English ones:

Readability index = 180 − average sentence length − (58.5 × average syllables per word)

The scale:

Value	Readability	Understandable for
0–30	very hard	academics
30–50	hard
50–60	fairly hard
60–70	medium	pupils aged 13 to 15
70–80	fairly easy
80–90	easy
90–100	very easy	pupils aged 11

For a business website, 60 to 70 is a good target range. That is the span in which most well-written newspaper texts lie.

Free tools for this: fleschindex.de calculates the German value, wortliga.de/textanalyse analyses further and makes suggestions for improvement. Word has built-in readability statistics under Home, Editor, Insights.

One caveat, because such values like to be over-interpreted: the formula counts syllables and sentence lengths. It understands nothing. A text of short but empty sentences gets a good value. The index is a hint about where to look — not a verdict on the text.

The corresponding rule is success criterion 3.1.5 “Reading Level” and sits at level AAA. It names lower secondary education level as the yardstick. For some target groups that is unrealistic — a supplier of wind turbines for industrial customers necessarily writes in a complex way. The guiding idea still stands: write so that it is understood.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.2)

Leichte Sprache and Einfache Sprache are two different things

These two German terms — literally “easy language” and “plain language” — are constantly confused. They mean different things with different target groups.

Einfache Sprache

A simplified form of standard language, less strongly reduced. It is aimed at people who have difficulties with complex texts: people with lower reading and writing skills, people with German as a second language, language learners. Explicitly not at people with cognitive impairments.

It is standardised: DIN ISO 24495-1 from 2023 sets out four basic principles:

1. Relevance — the reader gets what they need.
2. Findability — they find it easily.
3. Understandability — they understand it easily.
4. Usability — they can easily apply it.

The German supplementary standard DIN 8581-1 from 2024 makes this concrete for the German language.

The rules largely match what is above: no foreign words, no abbreviations, strong verbs instead of noun constructions, active instead of passive, no proverbs and metaphors, no negations, no synonyms — stick to one term. Sentences of at most 15 to 20 words, ideally one comma per sentence, no nested subordinate clauses.

Einfache Sprache is the right standard for most business websites. It costs nothing but attention while writing and improves the text for all readers.

Leichte Sprache

A strongly reduced special form. It is aimed at people who have difficulties reading and understanding standard texts — above all people with learning difficulties and cognitive impairments.

The difference in effect:

Standard: “By registering on our website you gain access to a wide range of resources specifically geared to meeting your individual needs.”

Leichte Sprache: “You can sign up on our website. Then you can use many things. These things help you.”

Leichte Sprache has its own, very concrete rules — not only for the language, but also for the design:

• Simple typeface, at least font size 14.
• Line spacing 1.5.
• Always left-aligned.
• Every new sentence starts on a new line.
• No hyphenation at the end of a line.
• Images yes, but not as a background.
• Highlight what is important.
• No questions in the text.
• No abbreviations — “das heißt” instead of “d. h.” (“that is” instead of “i.e.”).
• Phrase positively — “That was good” instead of “That was not bad”.

There is no binding standard for it yet; a draft (DIN SPEC 33429) has existed since 2023. The detailed rules are provided by the Netzwerk Leichte Sprache.

Leichte Sprache is a discipline of its own. Translations are made by trained translators and checked by people from the target group. There are now AI translations for it, but their quality does not yet reach that of trained translators and checkers.

Whether Leichte Sprache is required for a particular website depends on which set of rules applies to it — that is a legal question to be clarified in the individual case. As a voluntary offer, a page in Leichte Sprache is possible in any case and works.

(Rheinwerk, Barrierefreie Webseiten, ch. 5.3 and 5.4)

What the text looks like counts too

Three points that belong to comprehensibility but are design questions:

Left-aligned, not justified. Usability tests repeatedly show that left-aligned ragged text is read and understood fastest. Justification creates uneven word spaces, in the worst case white channels running vertically through the paragraph — a real reading hurdle for people with cognitive impairments.

No centred running text. With centred text the eye has to search for the start of the next line at the end of each line, and it slips while doing so. For a heading that is fine, for a paragraph it is not.

Enough line spacing, more paragraph spacing. The spacing between paragraphs should be at least 1.5 times the line spacing, so that the paragraph break stays visible.

How to check it yourself

The skim test. Look at your page for ten seconds, then look away. What do you know now? If the answer is “nothing”, your headings and highlights carry nothing.

The read-aloud test. Read your text aloud. Where you have to take a breath in the middle, the sentence is too long. Where you stumble, the reader stumbles too.

The foreign-word pass. Go through the text and mark every word a customer would not use. Technical terms, anglicisms, officialese. Each of them is a decision: explain or replace.

Count the sentence length. Not everywhere — find the three longest sentences on the page and split them.

The readability index as a rough bearing, with the caveat above.

And the most honest test: give your text to someone who does not work in your industry, and afterwards do not ask “Was that understandable?”, but “What do we offer, and what does it cost?” The answer shows what actually came across.

What to do

Start with the pages that earn money. Home page, services, contact. The blog post from 2021 can wait.

Shorten the sentences before you swap the words. Sentence length has a stronger effect than word choice.

Rewrite the headings. They do the most work and are the quickest to change. A heading that actually describes the section helps the skimmer, the screen reader user, the search engine and the AI system — four results for one change.

Pull enumerations out of sentences.

And write your customers' language, not your own. The most common reason for incomprehensible business texts is not a lack of skill but blindness to your own trade: you write in the language you use with colleagues. But the customer searches for other words — and therefore does not find the page in search engines either.

Sources

• Rheinwerk, Barrierefreie Webseiten, ch. 5.1 (visual information search and cognitive ease) — the three phases of skimming, scanning and detailed reading with the role of bold keywords as anchors, the corresponding behaviour in screen reader use via the main heading and further headings, the importance of expected positions and self-explanatory icons, the terms skeuomorphism and affordance, and cognitive ease after Kahneman with the levers consistency, short clear sentences and multichannel presentation.
• Rheinwerk, Barrierefreie Webseiten, ch. 5.2 (designing texts for the target group) — the finding that authors are perceived as more intelligent with simple language, and the connection between a hard-to-read typeface and a negative assessment of the author, the Hamburg comprehensibility model by Tausch, Langer and Schulz von Thun with its four features, the practical checklist for web texts, WCAG 3.1.5 “Reading Level” with the reference to lower secondary level and the restriction for specialist target groups, WCAG 3.1.3 on unusual words, the readability formulas including Toni Amstad's German Flesch adaptation with complete formula and scale, the tools fleschindex.de, Wortliga and the readability statistics in Word, the recommendations from WCAG technique G153 including the sentence length of 15 to 20 words, WCAG 3.1.4 on abbreviations with the note to prefer spelling out to the <abbr> element, the problem of idioms and metaphors with two German examples, and the notes on left-aligned text, centred text and paragraph spacing (WCAG G169 and G188).
• Rheinwerk, Barrierefreie Webseiten, ch. 5.3 (Leichte Sprache) — target group and degree of reduction, the before-and-after example on registration, the draft standard DIN SPEC 33429 from 2023 and the Netzwerk Leichte Sprache as the source of rules, the rules on words, sentences and text, the design rules on typeface, font size 14, line spacing 1.5, left alignment, a new sentence on a new line, no hyphenation and images, and the assessment of the quality of AI translations compared with trained translators.
• Rheinwerk, Barrierefreie Webseiten, ch. 5.4 (Einfache Sprache) — the distinction from Leichte Sprache and the explicit definition of the target group, DIN ISO 24495-1 from 2023 with the four basic principles relevance, findability, understandability and usability, DIN 8581-1 from 2024 as the German supplementary standard, the rules on words and sentences including the recommendation of one comma per sentence.
• Atlas, accessibility/criteria/ — classification of the named success criteria by principle, guideline and conformance level.
• Own audit practice — the order of effectiveness of the individual rules, the caveat on the meaningfulness of readability indices, the recommendation of a target range of 60 to 70, the skim test, the read-aloud test, the foreign-word pass, the wording of the question when testing with outsiders, and the note on blindness to your own trade as the most common cause of incomprehensible business texts, together with its effect on findability.