Verbose text is extremely costly on a braille display
Aliases: verbose alt text · braille cost · long description tax
What it is
A string that takes two seconds in speech may take seven or eight pans on a braille display. Verbosity is noise in speech and labor in braille. Display users pay in cells and pans, not in how chatty it sounds.
Why it happens
Speech compresses: rate, skip, and interrupt all cut the cost of a long sentence. Braille is felt character by character; the window emits only a few dozen cells, so a long description is billed nearly linearly — double the characters, double the pans. Readers often send the same string to speech and braille, so a length written to “sound all right” is charged in full on the tactile channel.
Repeated boilerplate, alt text that restates a visible heading, adjectives stacked for “completeness,” all spend cells on characters with no new information. Speech users can fast-forward; display users have to crawl across those characters before they reach the control they actually came to operate.
Studying it
Make two versions of the same figure, short and long. Braille output only (or speech off, display only). Ask people to report the fact the figure is meant to carry, then continue to the next action.
Independent variables: character count, whether a heading is repeated, cell count. Dependent variables: pan count, time to the fact, time to the next control, whether reading is abandoned mid-string.
Compare the same pair in speech only: “a bit long” in speech is often already unacceptable in braille. Do not score “is the description complete” alone; complete but unfinished is not delivered.
Where it stops holding
Complex charts do need long material; that bill belongs at a separate entrance (visible long text, another page), not packed into a short name that will flood the display’s main window. Legally verbatim text cannot be cut for shortness, but it should be jumpable by section rather than bound to one control’s name. People who never use a display do not pay this labor; accepting length at their speech rate will miss the tactile channel.
Applying it
- Write names, alt text, and state words as if they occupy a twenty-cell row: function and fact first, repeated headings and adjectives gone.
- Put long material where the user can choose to read it; do not pour it into every braille row by default.
- How to check: speech off, read a figure and a button on a twenty-cell display. If several pans pass before the fact arrives, or a boilerplate tail follows the control, the description already costs more than it informs.