A New Language
For now, the Basque expressions I remember best are of the seriously pro-ETA bent because I encounter them most often in literature. I’m afraid when I meet actual speakers I will blurt out something in the vein of “etarra, etarra, gora ETA militarra”, and that will be very uncomfortable for everyone.
This reminds me of this Jewish fellow who traveled to the Netherlands and entered a business meeting with “Arbeit macht frei” as an ice-breaker. The Dutch businessmen did not appreciate the humor.