Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
FOREIGN PHRASES, FOREIGN WORDS, AND FOREIGNISMS
of all sorts have their place in American English, but they require restraint of author and speaker, and they demand a careful assessment of what the reader or hearer can easily understand. Never use foreignisms to impress others with your erudition; use them only when nothing else will do or when they contribute the precise tone you wish to achieve, but make dead certain that any you do use are used correctly and are bound to be understood by your audience or readers. Otherwise, stick with English.
