Hope you are doing well and sorry for the delay in response. I hope you would be able to solve it by now.
If the issue still exists, you need to install the additional languages in your OS's Text To Speech (TTS) preferences. Acrobat/Reader uses the engines available on your system. Once you add the additional language to your system go to Edit (Win), Adobe Acrobat (Mac) > Preferences > Reading >Uncheck 'use default voice' and select the desired language under 'Read out loud options' as shown in the screenshot below: