VocabularyShop uses the available Text to Speech (TTS) function from the Operation System (OS) to read words and texts to you. You should use the OS function to configure your TTS settings.
Windows 7, 8, and 8.1
clicking the Start button on the bottom-left of the screen > clicking Control Panel > in the up-right search box type in the word “speech” > click the “Change text to speech settings” line, the Text to Speech tab of the Speech Property window will pop up and you can select voice, change voice speed, and preview voice.

Windows 10
Click the Start icon on the bottom left corner of the screen > select Settings > in the search box, type in the word “speech”

> click the Change text-to-speech settings line, the Speech setting page will appear > move to the Voice section, you can choose voice, change voice speed and preview voice.

Adding New Voice in Windows 10
There are total 12 English voices offered by Windows 10. You need to install them to your system before you can use them. To add new voices, click the “+” sign next to the Add voices label, a dialog box will open and all available voice packages will be displayed.

You can type the word “English” in the input box on the top or click the individual checkbox for each voice, then click the Add button at the bottom to install the voices. Exit Setting to complete the installation. The newly installed voice can be selected when you enter the Setting next time.