"Parler français comme une vache espagnole" literally means "to speak
French like a Spanish cow." Less
literally, it means to speak French poorly. While Spanish cows probably don't speak French too well, it seems a little
cruel to pick on them for their lack of
linguistic ability; surely
American cows are much worse. In fact, the phrase is an example of
evolved nonsense-- several French websites pointed to its origins in the phrase
"parler français comme un basque l'espagnol." (In English, "to speak French like a
Basque speaks Spanish.")
More fun French cow phrases found at http://www.lavache.com/infos/proverb/proverb.htm.