If Scotland was attractive for immigrants, it would do a lot. Such a requirement would reduce immigration, but it would also rapidly increase the population of

If Scotland was attractive for immigrants, it would do a lot. Such a requirement would reduce immigration, but it would also rapidly increase the population of Gaelic speakers. That being said, I find it highly unlikely that there is a country that both has a country with a dying language with enough demand for immigration that immigrants would be willing to revitalize the local language. That combination seems possible, but highly improbable.