How big should the cells be for the person who wants to communicate via touch, mouse, joystick or eye tracking?
Perhaps this pageset can help you determine this.
Run this evaluation, to determine which page settings result in accurate selections.
Inglese
Mouse/Touch Puntamento oculare
SymbolStix
<5 Scuola primaria Scuola secondaria Adulti
Mind Express 5
Gratuito
"*" indica campo richiesto