Perceivable
WCAG 1.3.3
Sensory Characteristics
Instructions can't depend on shape, size, position, or sound alone. "Press the round green button on the right" fails for anyone who can't see it — always add a text label: "Press Submit".
In plain terms
Instructions can't rely on shape, color, or position alone. 'Click the green button on the right' fails for people who can't see it — name it too.
Why this matters
Instructions that rely on shape, size, position, or sound alone fail anyone who can't perceive that cue — blind users hearing 'the button on the right', or deaf users told to 'wait for the beep'.
How to detect
Quick check
Scan instructional text for cues like 'click the round button', 'the box on the left', or 'when you hear the tone'. Each should also name the thing in text — 'select Submit'.