A half-remembered, and possibly apocryphal, story which another mathematician once told me:
Langlands was once invited to lecture in France, and he chose to give his talk in French. Evidently his accent was not all that good, and the audience found it a bit painful.
Jean-Pierre Serre, one of the leading mathematicians of the 20th century, and a Frenchman, was attending the lecture that day. He interrupted to ask a question, in English.
Declining to take the hint, Langlands answered in French and carried on with his lecture.
Langlands was once invited to lecture in France, and he chose to give his talk in French. Evidently his accent was not all that good, and the audience found it a bit painful.
Jean-Pierre Serre, one of the leading mathematicians of the 20th century, and a Frenchman, was attending the lecture that day. He interrupted to ask a question, in English.
Declining to take the hint, Langlands answered in French and carried on with his lecture.