Most, probably, have a strong attachment to a common language as an essential element of unity. The essence of human relationships is the ability to communicate. Since language is the vehicle of communication, a common one is a prerequisite.
As I have made note before, the essentiality of a common language to human endeavor is emphasized early in the biblical story. The account of the Tower of Babel demonstrates as much and suggests that a universal language would enable the greatest of human achievement.
I suspect we all would admit, at least to ourselves, that hearing a strange language is troubling. When we cannot know a person from at least hearing them speak, it raises a barrier of confusion and even suspicion.
Within our national politics it is noteworthy how there is no common language. Countless terms and labels are passed out in connection with individuals and policies, terms which have no concrete meaning. The language of politics is often a deliberate attempt to misinform and confuse, so a common language is actually a detriment to political purposes. If a common language is essential to unity, our political practices work against that union.
If humanity ever unites under a common language what would that likely be? Linguists might suggest our own since it has become the language of commerce and diplomacy around the world.
This issue of a universal language reminds me of the old question about what language did God use in speaking with Adam in the Garden. Some have suggested Hebrew as the divine language in that context. I suspect the God language is beyond mere words. God is love, and love is the divine language. That divine language opens the possibility of human unity on a far greater scale than any other language possibly could.