Improving FlexType: Ambiguous Text Input for Users with Visual Impairments

Dylan Gaines, Keith Vertanen

Abstract: We present an improved version of the FlexType interface for nonvisual text input. FlexType enables nonvisual text input on mobile touchscreen devices by allowing users to select from a small number of character groups with gestures instead of targeting letters at specific screen locations. Based on an interview with users who are blind or low vision, we added a letter-entry mode to enable easier entry of difficult words such as proper nouns. We conducted a longitudinal study with users who are legally blind to compare FlexType to users’ typical text input methods. While we found FlexType was significantly slower than Apple’s onscreen Braille input, there was no significant difference in entry or error rate between FlexType and an onscreen keyboard with VoiceOver enabled. This was despite the participants having much more experience with the VoiceOver keyboard compared to FlexType. Overall, legally blind participants averaged 7.7 words per minute with a 7.0% character error rate after correction when writing with FlexType.