The SpeechSynthesis interface of the Web Speech API is the control interface of the speech service; it can be used to obtain information about the available synthesized sounds on the device.
We can use the browserleaks website to detect the list of Speech Voices, show as follows:
The result of the above figure is set customized by VMLogin. The new configuration interface is as follows:
When some websites use this technology to fetch the Speech Voices list, then Vmlogin will be able to customize the fingerprint of Speech Voices.