We could update our previous example to add a 10 millisecond rest after the cue is sounded to prevent run-ins as follows:

h1 {
    -epub-pause: 50ms 25ms;
    -epub-cue: url('audio/ping.mp3') none;
    -epub-rest: 10ms 0ms
}

But again, if I didn’t say it forcefully enough earlier, it’s best not to tweak these properties unless you’re targeting a specific user group, know their needs, and know that their players will not provide sufficient quality “out of the box.” Tread lightly, in other words.

A final property, that is slightly more of an aside, is voice-family. Although not specifically accessibility related, it can provide a more flavorful synthesis experience for your readers.

If your ebook contains dialogue, or the gender of the narrator is important, you can use this property to specify the appropriate gender voice. We could set a female narrator as follows:

body {
    -epub-voice-family: female
}

and a male class to use as needed for male characters:

.male {
    -epub-voice-family: male
}

If we added these rules to a copy of Alice’s Adventures in Wonderland, we could now differentiate the Cheshire Cat using the male voice as follows:

<p>
    Alice: But I don't want to go among mad people.
</p>

<p class="male">
    The Cat: Oh, you can't help that.
    We're all mad here. I'm mad. You're mad.
</p>

You can also specify different voices within the specified gender. For example, if a reading system had two male voices available, you could add some variety to the characters as follows by indicating the number of the voice to use:

.first-male {
    -epub-voice-family: male 1
}

.second-male {
    -epub-voice-family: male 2
}

At worst, the reading system will ignore your instruction and only present whatever voice it has available, but this property gives you the ability to be more creative with your text-to-speech renderings for those systems that do provide better support.

Whatever properties you decide to add, it is always good practice to separate them into their own style sheet. You should also define them as applicable only for synthetic speech playback using a media at-rule as follows: