The speech synthesizer 1712 artificially produces human speech. For example, a text-to-speech speech synthesizer may convert normal language text into speech; other embodiments of the speech synthesizer 1712 may render symbolic linguistic representations such as phonetic transcriptions into speech. As shown in FIG. 17A, the speech synthesizer 1712 generates the speech signals 1714 from the textual message 1710. The speech synthesizer 1712 may be implemented in software or hardware. For example, the speech synthesizer 1712 may be part of a personal computer (PC), a tablet PC, a set-top box (STB), a smartphone, an internet of things (IoT) appliance, or any machine capable of executing instructions that specify actions to be taken by that machine. In one embodiment, the speech synthesizer 1712 maps the textual message 1710 to stored sound signals. For example, the speech synthesizer 1712 may generate the speech signals 1714 by concatenating pieces of recorded speech signals (sound signals) that are stored in a database. In alternative embodiments, the speech synthesizer 1712 may incorporate a model of the vocal tract and other human voice characteristics to create a completely “synthetic” voice output.
