Text-To-Speech Technology for Dual Party Relay Services

We evaluated several human factors issues involved in applying AT&T Text-to-Speech (TTS) technology to Dual Party Relay (DPR) services for hearing- or speech-impaired end-users. Covered in this paper are: 1) lexical studies that were conducted to gather abbreviations and typographical errors generated by users of the Telecommunications Device for the Deaf (TDD); and 2) a laboratory trial that was performed to evaluate the feasibility of the TTS application and to examine associated user interface issues.

Information gathered from the lexical studies was used for the laboratory trial and for constructing the field trial system. The laboratory trial consisted of several studies, including a comparison between the comprehension of TTS and human voices, identification of a desirable TTS presentation rate, examination of the effects of pauses, and observation of the difficulties related to TTS relay calls. Recommendations were made based on the lab trial results. We concluded that applying TTS to DPR service is feasible. That is, hearing and hearing-impaired subjects can carry on DPR conversations with the use of TTS technology. A field trial was subsequently conducted in California.