Koe Palette — AAC & Switch

SignCascade UD

In-app purchases

About this app

Koe Palette turns your Android phone or tablet into a voice.

Tap a card — the device speaks. That is the whole idea. Everything needed to communicate is free, and always will be.

■ Built for people who cannot tap

Not everyone can reach a screen. Koe Palette speaks through the input you already have:

- Switch access — one or two switches, with adjustable scan speed and hold time
- MIDI pads — connect a pad controller and speak with a single press. Pads light up by category, so you can see where you are without reading
- USB keyboards and HID devices — assign any key to any card
- Direct touch, with guard time and long-press confirmation to prevent accidental speech

■ Works without the internet

Speech is generated on the device. No account, no connection, no waiting. It works in a hospital room, on a bus, in a classroom with no Wi-Fi.

■ Make it your own voice

Record a real voice — a parent's, a sibling's, a teacher's — and attach it to any card. Trim silence, tag recordings, and reuse them across the whole board. A card can show a photo you took instead of a symbol.

■ Designed to be readable

- Colour vision deficiency support with 4 modes
- Shape indicators, so a card is identifiable without relying on colour alone
- Adjustable text size and font
- Minimum 48x48 touch targets throughout

■ 400+ cards, ready on day one

16 categories covering greetings, requests, feelings, daily life and emergency. Pick a board size when you start — small for a first board, large for a full vocabulary — and edit anything from there. Add tabs, reorder cards, move them between categories.

■ For teachers and carers

- Education mode with a PIN lock, so the board cannot be rearranged mid-lesson
- An emergency card and a toilet button that stay reachable at the top of the screen
- Favourites that surface the cards actually being used
- Compose mode for building a sentence before speaking it

■ Languages

The app is available in English, Japanese, Chinese (Simplified) and Indonesian. You choose the language the first time you open it, and can change it any time in Settings. The words shown on the cards and the words spoken aloud can even be set to different languages — for when the reader and the listener are different people.

■ What is free

Speaking is free. Cards, recording, switch and MIDI access, colour and font settings, education mode and the emergency card are all free, with no ads.

An optional Pro subscription adds convenience features for people who want them — advanced audio editing and full access to multiple MIDI devices. It never gates communication itself.

■ About us

Koe Palette is made by SignCascade UD, a small Japanese developer working on accessibility and universal design. If something is wrong or missing, tell us — we read every message.

What’s new

■ Now in four languages
Japanese, English, Chinese (Simplified) and Indonesian. Choose on first launch, change any time in Settings. The cards and the spoken words can be set to different languages.
■ A toilet button at the top
One tap from any page. Turn it off in Settings.
■ Clearer speech
Fixed mispronounced words and adjusted the speaking speed.
■ Tidier settings
Five tabs: Display, Audio, Devices, Access and Manage.
The five sample recordings, which had no audio, were removed.