Most of the words above are considered informal (e.g. "chavo(a)", "padre", "güero", etc.), rude ("güey", "naco", "¿cómo (la) ves?", etc.) or vulgar (e.g. "chingadera", "pinche", "pedo") and are limited to slang use among friends or in informal settings; foreigners need to exercise caution in their use. In 2009, at an audience for the signing of a Memorandum of Understanding between Mexico and the Netherlands, the then Crown Prince of the Netherlands, Willem-Alexander, made a statement to the audience with a word which, in Mexican Spanish, is considered very vulgar. Evidently oblivious to the word's different connotations in different countries, the prince's Argentine interpreter used the word "chingada" as the ending to the familiar Mexican proverb "Camarón que se duerme se lo lleva la corriente" (A sleeping shrimp is carried away by the tide), without realizing the vulgarity associated with the word in Mexico. The prince, also unaware of the differences, proceeded to say the word, to the bemusement and offense of some of the attendees.