Ionesco said that The Bald Prima Donna, his first play, and a keystone of absurdist theatre, was inspired by a teach-yourself-English manual. He wrote in his autobiographical work on the theatre, Notes and Counter-Notes:
I bought an English-French conversational manual for beginners. I set to work. Conscientiously I copied out phrases from my manual in order to learn them by heart. Then I found out, reading them over attentively, that I was learning not English but some very surprising truths: that there are seven days in the week, for example, which I happened to know before; or that the floor is below us, the ceiling above us, another thing that I may well have known before but had never thought seriously about or had forgotten, and suddenly it seemed to me as stupefying as it was indisputably true.The play drew on these banalities, spiced up with a few well-known English proverbs (‘He who sells an ox today, will have an egg tomorrow’), and was originally called English Without Pain — but when a director commented that this might lead people to believe it was a satire on the English, this was changed to The Bald Prima Donna.
This title actually emerged during rehearsals. In the episode called 'The Headcold', the script refers to an ‘institutrice blonde’ (blonde schoolmistress); instead, the actor, Henri-Jacques Huet, made a slip – or began improvising – and said ‘cantatrice chauve’ (bald prima donna). Ionesco was present at the rehearsal and realized this was a much better phrase, and indeed a better title. It was adopted, and for form’s sake, a brief reference to a bald prima donna was later inserted in Scene 10.
Lamont, Rosette C.: Ionesco's Imperatives (1993)
Esslin, Martin: The Theatre of the Absurd (1980)