An Etymological Dictionary of the German Language/Pfirsich
Pfirsich, m. and f. (s after r as in Mörser and Hirse; yet Suab. pfêršiχ), from the equiv. MidHG. pfërsich, m., ‘peach’ (comp. Ital. pesca, Fr. pêche, whence E. peach). Although the word is not recorded until the 12th cent., Lat. persicum was naturalised in Germany even prior to the OHG. period (so too in England; comp. AS. persoc), as the permutation of the initial p to pf indicates (comp. Lärche and Pflaume), while Birne was adopted within the latter era. With regard to the gender see Pflaume. With the introduction of horticulture and fruit-growing from the South, numerous names of fruit passed into G.; see Kirsche, Pflaume, and pfropfen.