Some aspects of synthetic elderly voices in ambient assisted living systems

Senior citizens are in the focus of current research in Europe. This paper investigates the usability aspects of synthetic voices intended for elderly people in Ambient Assisted Living (AAL) systems. The first topic of the study is the selection of an appropriate age of Personal Life Assistant´s (PLA) voice intended for active seniors. The second topic is whether the user´s own voice is feasible in personal messages. Third, the use of rather short speech corpora from elderly people for HMM speaker adaptation is studied. The question is whether adapted voice is categorized to the same age group by listeners as the original. Corpus based unit-selection TTS and adapted HMM-TTS voices were created from elderly speech samples and these are compared to other middle-aged and elderly voices. In listening tests the synthesized sentences were evaluated and compared to natural speech samples by elderly test subjects. The authors found that the TTS voices of more pleasant (younger) speakers are preferred, HMM-TTS adapted voices of elderly speakers retained age identification features of the original recordings and are suitable for personal messages.