Confused by automatic language switching on the Mac

macOS & Mac Apps

Hello everyone,

Recently, I upgraded my Macbook pro to High Sierra, in which new feature I explored which delighted me is the automatic language switch that is what I believe as per my understanding. Is it the same as in Ios where the text of particular language or script is read by that particular voice of the language with automatic switching. If so, the feature is not working in my mac or moreover maybe the chances that I couldn't manage to rightly set it. I tried in the speech pane of voiceover utility as I needed the Hindi voice to read the texts in my language i.e. in devanagari script but the language is not switched. I also added the language from add language in speech tab of utility but couldn't manage. Even through shortcut menu of selecting rate, voice and so on and selected 'automatically select' option but still couldn't manage.
Help me through it .