Common language enables global communication
Language is a tool that allows us to communicate. Two languages defeat the purpose. We should agree on One Language that all citizens speak, read and write to enable common systems and processes to be communicated and applied efficiently. Administration then becomes more efficient.
Extra languages, whether regional or otherwise, are fine, as long as one common language is maintained and used for all official documents and signage.
Risks: Other Languages are key tools used to separate Us from Them. Mitigated by an enforced global language.