Best AI reading tool?

I am trying to learn a new language. At my Job I sometimes have to stare at a monitor for 2-3 hours only to watch over some patients. I am allowed to listen to music but not to read or watch my mobile. So my Idea was to creat sentences and word with an AI speaking tool and listen to them. I tried elevenlabs ( I think this was the name) but it is expensive like hell and the speakers are getting super fast when I give the program more then 10 sentences. Do you have any recommendations? I am learning Korean btw so maybe something with Korean voice.