Short message dictation on Symbian series 60 mobile phones

Dictation of natural language text on embedded mobile devices is a challenging task. First, it involves memory and CPU-efficient implementation of robust speech recognition algorithms that are generally resource demanding. Secondly, the acoustic and language models employed in the recognizer require the availability of suitable text and speech language resources, typically for a wide set of languages. Thirdly, a proper design of the UI is also essential. The UI has to provide intuitive and easy means for dictation and error correction, and must be suitable for a mobile usage scenario. In this demonstrator, an embedded speech recognition system for short message (SMS) dictation in US English is presented. The system is running on Nokia Series 60 mobile phones (e.g., N70, E60). The system's vocabulary is 23 thousand words. Its Flash and RAM memory footprints are small, 2 and 2.5 megabytes, respectively. After a short enrollment session, most native speakers can achieve a word accuracy of over 90% when dictating short messages in quiet or moderately noisy environments.