Contact between culturally distinct human groups in the contemporary ‘glocal’ -global and local- world is much greater than at any point in history. The challenge we face is the identification of the most convenient ways to organise the coexistence of different human language groups in order that we might promote their solidarity as members of the same culturally developed biological species. Processes of economic and political integration currently in motion are seeing increasing numbers of people seeking to become polyglots. Thus, (...) English is establishing itself as the usual world supra-language, although it coexists with other lingua francas that are widely used in certain parts of the globe. All this communicative reorganization of the human species may very well pose new problems and aggravate existing tensions as regards language and identity. It would seem that these processes comprise at least four major conceptual dimensions which must be taken into account above all else, as they are both widespread and, left unaddressed, may lead to significant social instability. These dimensions concern linguistic recognition, communicability, sustainability and integration. While accepting the utility of having an inter-national language, the keystone of the system is clearly that it must ensure the linguistic sustainability of each group. The basic principle is likely to be functional subsidiarity, i.e., whatever can be done by the local language should not be done by another one which is more global. As in the quote from Paracelsus --“the dose alone makes the poison”-- contact between languages is not ‘poisonous’ per se, but when the correct dose is exceeded it can prove harmful to the language whose position is weaker. A multilingual and communicated humanity is possible. (shrink)