Excuse my French

[disturbed]

where does the saying ' Excuse my French' come from?

[Quizmonster]

It has long been the case that nations blame their neighbours - especially those very close and against whom wars have been fought - for all sorts of failings. Thus, we make fun of �Dutch courage', which appears only if the Dutchman is drunk. Similarly, our slang for a condom includes the word �French' and theirs includes �English'. When we skive off, we take �French leave' and when they do, they take �English leave'.
�Excuse my French' is very much in the same mould. The suggestion is that there is no such thing as a �bad word' in English, so - if someone imagines they heard one, they must have misheard it as French...or "I was really speaking French!"

[colin58]

http://www.phrases.org.uk/meanings/130800.html
This website shows
Meaning
Please forgive my swearing.
Origin

A coy phrase used when someone who has used a swear-word attempts to pass it off as French. The coyness comes from the fact the both the speaker and listener are of course both well aware the swear-word is indeed English.

This is mid 20th century English in origin. A version of it is found in Michael Harrison's All Trees were Green, 1936:

"A bloody sight better (pardon the French!) than most."

The precise phrase comes just a few years later in S.P.E. Tract IV., 1940:

"Excuse my French! (forgive me my strong language)."