Mayday first came into English in 1923. There was a lot of air traffic between England and France in those days, and evidently there were enough international problems over the English Channel that both parties wanted to find a good distress signal that everyone would understand.

What is the origin of Mayday?

The Mayday call originated in the 1920s. ... As much of the traffic at Croydon airport at that time was to and from Le Bourget Airport in Paris, Mockford proposed the expression “Mayday" derived from the French word “m'aider" that means “help me" and is a shortened form of “venez m'aider", which means “come and help me".

Is Mayday a universal term?

A sure sign of spring in northern latitudes, Mayday also happens to be the universal term to signal a life-threatening emergency.