Reciprocal agreement with the EU on the transfer of UK CAA Flight Crew Licences.

[Bus Driver Man]

There are other nationalities working at Air France, Lufthansa, Swiss and KLM. They speak French, German or Dutch.
They all meat the requirement of speaking the (or one of the) national language(s). There's nothing unfair about that.
A language requirement and a requirement for the right to work in that country is not discriminating.