Speech-synthesis device having user dictionary control

In a speech-synthesis device, it is possible to determine whether or not a user dictionary that supports processing for reading aloud a specific phrase associated with specific reading should be used. The speech-synthesis device includes a speech-synthesis unit configured to perform read-aloud processing, a user dictionary provided to support processing for reading aloud a specific phrase associated with specific reading, and a control unit that includes a plurality of functions achieved by using information about the read-aloud processing, that determines whether or not the user dictionary should be used according to which of the functions is used so as to perform the read-aloud processing, and that makes the speech-synthesis unit perform the read-aloud processing.