Designing for a Wearer Who Cannot Read the Interface
When your user may not share a language with your product, the correct amount of interface is almost none. What that constraint forces you to get right instead.
· 7 min read
The constraint
Our wearer might read Bahasa Indonesia, Bengali, Hausa, Urdu, Turkish, Malayalam or none of the above. They might be eighty-two years old and have never operated a touchscreen. They might be in early heat exhaustion, which degrades reading comprehension before it degrades walking. Any interface built from words fails somebody in that set, and the people it fails are exactly the people the product exists for.
So: one key, and a screen the wearer never has to operate
The watch has a screen, and the discipline is in what we refuse to put on it. A screen invites you to solve problems by writing words on it, and words are the thing we cannot rely on. So the screen shows the time, the date of the rite and one line about where the wearer is standing, and the guide says that line aloud in their language. There is exactly one input the wearer has to know: the side key, held for three seconds. The design problem becomes making that one input unambiguous.
Haptics carry the whole conversation
Everything the watch says back to the wearer is also vibration, so that nothing safety-critical depends on reading. The patterns are deliberately few and deliberately distinct. Two short pulses: your alert went out. A long slow pulse repeating: someone has acknowledged and is coming to you. A distinct triple pattern: stay where you are, somebody is walking toward you. A single soft pulse: your family is calling, press once to answer. Four messages, learnable in ninety seconds at fitting, in no language at all.
Why the key needs a three-second hold
An SOS key on a wrist worn in the densest crowd on earth will be pressed by accident, and a system that cries wolf forty times a day gets ignored by the people who have to respond to it. Requiring a deliberate three-second hold, with a countdown the wearer can cancel, is what makes the alert meaningful when it arrives. The three seconds are also long enough for the wearer to change their mind, which matters more than it sounds.
The complexity has to live somewhere
None of this makes the system simple; it relocates the complexity to the people who can handle it. The group leader has a console with maps, lists and priorities, and they are trained on it, indoors, before the season. The family has an app, and they are at home and calm. The wearer has one key, a voice that speaks their language, and four vibrations. Deciding who carries the cognitive load, and putting almost none of it on the person in difficulty, is the actual design work.
What we still have not solved
Confirming that a wearer has understood the four patterns is currently a human process at fitting, and it depends on the quality of the briefing. We do not have a good way to verify comprehension at scale, and pretending otherwise would be dishonest. It is the open problem we would most like the pilot season to teach us about.