We love to use beaucoup words borrowed from foreign languages in English. In this case, we stole “beaucoup,” meaning “many” or “much,” from French. While “beaucoup” was pulled into English as early as the mid-18th century, when French vocabulary was the height of fashion, this word in particular became much more popular with American GIs coming home from Europe and Vietnam in the 20th century. The pronunciation evolved into “boo-koo” and the usage was much more casual.