Situational awareness is enhanced by single language communications. However, there is little point if everyone is 'forced' onto a non-native language (pilots and controllers) to facilitate the one a day/week/month/year English only operator. Obviously it would be up to local regulators to determine the language(s) to be used; I hope that these regulators are constantly reviewing things based upon reports where situation awareness or language issues arise and subsequently when necessary changes are made to SOPs.
The other issue is non-radio communications and it's general degradation to situational awareness; things like CPDLC/ACARS and other forms of Datalink where information can be relayed without voice comms; providing no-one with situational awareness regardless of the language used.