Mobile, Hands-free, Silent Speech Texting Using SilentSpeller

Abstract

Voice control provides hands-free access to computing, but there are many situations where audible speech is not appropriate. Most unvoiced speech text entry systems can not be used while on-the-go due to movement artifacts. SilentSpeller enables mobile silent texting using a dental retainer with capacitive touch sensors to track tongue movement. Users type by spelling words without voicing. In offline isolated word testing on a 1164-word dictionary, SilentSpeller achieves an average 97% character accuracy. 97% offline accuracy is also achieved on phrases recorded while walking or seated. Live text entry achieves up to 53 words per minute and 90% accuracy, which is competitive with expert text entry on mini-QWERTY keyboards without encumbering the hands.