Sylvia Plath's father, Otto Emil Plath, was also a native German speaker. Born in 1885 in the German town of Grabow, he emigrated to America in his 'teens.
He died on 5 November 1940 (following a leg amputation made necessary by the complications of untreated diabetes) just a week or so after Plath's eighth birthday.
In this line from The Bell Jar, there is a hint, perhaps, of the passionate resentment which Sylvia Plath felt against her own father, which is so vehemently expressed in her poem 'Daddy', written in 1962. Interestingly, in the poem she says, 'I was ten when they buried you'.
Sylvia Plath reads 'Daddy':