Working offline

Also called Offline use, Offline AAC, No signal

Why a communication aid must keep working with no signal, no Wi-Fi and no server, and how to check whether yours does before you find out in a lift.

What it is

A communication aid works offline if everything it needs to speak, the pages, the symbols, the voice, the settings, lives on the device itself, so that it behaves identically with the network off. An aid that needs a server to fetch a page, generate a voice or check a licence stops being a voice whenever the connection does.

Connections fail in lifts, basements, hospitals, rural lanes, on trains, at the seaside, and when the bill is unpaid. A voice cannot have those gaps.

Who it can help

Every AAC user, without exception. It matters most for people whose aid is their only means of asking for help: non-speaking people who live alone or with rotating carers, people in hospital, where Wi-Fi is patchy and mobile signal is worse, children on school trips, anyone out and about.

It is also a fairness issue. A person on a pay-as-you-go phone with no data allowance has as much right to speak as anyone with unlimited data, and an app that needs a connection quietly excludes them.

How it works

Native apps and dedicated devices generally store everything locally; the risk is in features bolted on later: cloud symbol libraries, online voices, sign-in checks, subscription validation. Web apps can work offline too, if they are built to cache themselves and their voices on first load, so that opening them later needs no network at all.

Voices are the usual gap. High-quality voices that stream from a server sound wonderful and vanish with the signal; voices installed on the device keep speaking. Speech recognition and cloud word prediction are the other common dependencies. The test is simple: aeroplane mode, then use the aid for a day.

Getting started

Today, put the device in aeroplane mode and use it for an hour: open every page, speak from every set, change a setting. Anything that fails or slows is a dependency, and the person deserves to know about it before the lift does.

Fix what you can: download the voices, turn off any online-only prediction, and make sure the app has been opened at least once on the current version while online so that it has everything cached. Then keep a low-tech backup in the bag anyway, because batteries run down as well.

Where to get help

Ask the app or device maker, in writing, whether it works fully offline and which features do not; the specialised AAC services will know for the devices they supply. Communication Matters and the ACE Centre publish guidance on choosing apps, and AbilityNet can advise on device settings that affect offline use.