G-BPEC
The actual ICAO policy which I've now located, although I don't necessarily agree with, is that in international aviation communications the primary language to be used in air-ground communications is that of the ground station (typically the notified language of the country in which the ground station is located). If English is not the language of the ground station however, ATC services should be made available in English on request. English is recognised by ICAO as the universal medium for communications.
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10 West
UK ATC'er
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