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Speech parameters

Language selection

Various synthesizers provide different sets of possible languages, they are allowed to speak. We must be able to receive a request for setting particular language (using ISO language code) and reply, if the language is supported.

Speed

Sped of the speech is supported by all synthesizers, but the values and their ranges differ. Each output module is responsible to set the speed to the value, best responding to current setting. This may be a little bit difficult, because there is no exact scale. We could take some longer english paragraph and take it as a base for our new scale. If this paragraph is said in eg. ten secconds, this means speed = 100, if it is said in twenty seconds, speed = 200. This way, we can coordinate diferent scales quite preciselly (the paragraph should be long enough).

Punctuation mode

Punctuation mode describes the way, in which the synthesizer works with non-alphanumeric characters. Most synthesizers support several punctuation modes. We will support a reasonable superset of those modes, which may be implemented in device driver, when not supported by hardware.

Prosody

Prosody setting allows us, to distinguish interpunction characters in spoken text, as we are familiar in normal speech. This means the way, we pronounce the text with interrogation mark, coma, dot etc.

Pitch

Pitch is the voice frequency. We face the similar problems here, as with Speed setting.

Voice type

Most synthesizers provide several voice types, such as male, female, child etc. The set is again different for each of the devices. Speech Daemon should try to find the nearest possible (if the request is child female and it's not available, we will try to use adult female rather then adult male).

Spelling

Spelling mode is provided by nearly all devices and is also easy to emulate in output module.

Capital letters recognition

That is again a widely supported feature. However it would be desirable to support this internally, using the sound icons feature, but this requires a good possibility of synchronization, which is not possible with all devices.