Chinese languages just missed out in the US based on very rough estimates I did with the most spoken one being about 1.37m.
Vatican City isn't here since there aren't any statistics for it
Numbers for small countries, island countries and a lot of Africa (especially central and western) are very rough due to the relatively small amount of info.
* next to a language means it's including a disputed territory
Scots could be under United Kingdom but there are no numbers for L1 speakers