"My younger brother was at that moment on the Experiment in International Living in Berlin and speaking German like a native"

Sylvia Plath's younger brother Warren did spend some time in Germany in June 1956 (which was several years after the period covered in The Bell Jar). He was there when Plath married Ted Hughes in London.

The 'Experiment in International Living' program was launched in America in 1932, and now operates in 28 countries. The parent body for the nationally-based organisations is known as Federation EIL.

The purpose of the program  is to allow young people to gain experience of other cultures through extended  visits to foreign countries, with the emphasis on participants immersing themselves in the customs and language of the host culture.