where did the saying pardon my french come from
Pardon my French At least one source[3] suggests that the phrase "derives from a literal usage of the exclamation. In the 19th century, when English people used French expressions in conversation they often apologized for it - presumably because many of their listeners (then as now) wouldn't be familiar with the language". The definition cites an example from The Lady's Magazine, 1830:[4]
La Marseillaise "La Marseillaise" (French pronunciation: ​[la maʁsɛjɛːz]) is the national anthem of France. The song was written in 1792 by Claude Joseph Rouget de Lisle in Strasbourg after the declaration of war by France against Austria, and was originally titled "Chant de guerre pour l'Armée du Rhin" ("War Song for the Rhine Army").