Auxilary artificial languages like Esperanto and Ido are designed for global communication. In what circumstances could a state realistically impose it from the top down? The closest IRL equivalent is Modern Hebrew in Israel, and that required the specific centrality of Hebrew (ironically as a liturgical language) to the Jewish identity.
Perhaps a World Government covering most of the Earth in a timeline less dominated by Anglophone nations could impose such a language.
The first, and biggest problem is getting people to speak it, and getting enough supporters that learning an esoteric language becomes part of the program. The second is culture - Esperanto largely failed to catch in part because it had no "artificial culture", and to what extent local cultures, like naming customs get overridden in the process. People may not want names in a foreign language like "Unueco Bakeristo" imposed onto them.
Perhaps a World Government covering most of the Earth in a timeline less dominated by Anglophone nations could impose such a language.
The first, and biggest problem is getting people to speak it, and getting enough supporters that learning an esoteric language becomes part of the program. The second is culture - Esperanto largely failed to catch in part because it had no "artificial culture", and to what extent local cultures, like naming customs get overridden in the process. People may not want names in a foreign language like "Unueco Bakeristo" imposed onto them.