Son of a bitch!

One of the finest examples of such confused borrowing occurs in a story told by the American linguist Charles Hockett. During the American occupation of the Philippines, at least one Filipino father named his son Ababís, after the patron saint of the USA. But no such saint exists. So what happened?
Before the American occupation, the Phillipines were a Spanish colony, and Spanish was widely spoken. In Spanish, the word for 'saint' when it occurs in a male saint's name is San - hence all those California place-names like San Francisco, San José, and San Diego. The father had noticed that American soldiers, in moments of stress, tended to call upon their saint by exclaiming San Ababís! - or something like that.

-RL Trask
Historical Linguistics