Windows 8.1/10/11

Note if installing from windows store to Windows 8.1, that you may not see Robot Talk on the start screen, however on your start menu it will appear under the group labelled 'Modern UI Applications'. Also on the start screen if you goto the bottom left corner of the start screen, a downward arrow will appear. Click on the arrow and a full list of all installed apps will appear. Next find 'Robot Talk', right click on it, and an options menu will appear, with the option to pin the app to the start screen.

Playto - to view more info on howto use a device with playto please go here

Casting - casting allows you to send the audio to another device such as a bluetooth speaker. The cast button in the app will list any capable device to send the audio to.
To add a new device you need to goto Settings, followed by the devices option. To send to a bluetooth speaker for example you need to turn the bluetooth option on.
Plus you can add a new bluetooth or other device via the add button. Also on the devices screen, you should see a list of all your other devices.
I got the bluetooth working with a various Bluetooth devices new/old. Was unable to Cast to a Smart TV.

Windows 8.1 Firstly, goto control panel.Under Clock,Language, and Region, click on the link labelled 'Add a language'. This will open a new screen called 'Language'. On the top part of the screen, click on the option labelled 'Add a language'.This will display a screen containing a list of languages available. Here click on one to add, then click on the add button at the bottom of the screen. This will then take you back to the 'Language' screen, here you can see the language you selected has been added to the list. Next, select the recently added language and click on the options link on the right-hand side.This will open a new screen labelled 'Language options', on this screen click on the link labelled 'Download and install language pack'. Repeat this operation, per language you wish to install. Please note for some reason, that certain languages such as Dutch, are not supported under Text-To-Speech. see this list - supported TTS voices before downloading

Windows 10 Via the start button click on settings.Next, click on 'Time & Language'.Next, click on 'Region & Language'.Then, click on 'Add a Language'.Next, click on a language to add. on the next screen select the same language again,then click on options.next, click on 'Download'.

Windows 10 v21h1 Via the start button, click on Settings. Next, click on 'Time & Language'. Next, click on 'Speech', on the left-hand side. Next, scroll-down to the option labelled 'Manage Voices', click on the button labelled 'Add Voices', to see a list of countries that you can add voices for. Below the 'Manage Voices' area, you should see a list of countries that you already have voices installed for.

Windows 11 Via the start button, click on the Settings icon in the Apps list. Next click on 'Time & Language' option on the left-hand side of the settings screen. Next on the main area of the screen, click on the option labelled 'Speech'. On the main area of the screen, scroll down to the area 'Manage Voices'. This area via the 'Add Voices' button, allows you the ability to select countries that you wish to add voices from. Also, below that area, you can see a list of those countries that you already have voices installed for.

Main screen at startup on Windows 8.1
Main screen at startup

Main screen at startup on Windows 10
Main screen at startup