Franglais is mixing English and French.
Wikipedia says that Franglais is "produced either by poor knowledge of one or the other language or for humorous effect" (http://en.wikipedia.org/wiki/Franglais)
It is more and more common these days, especially the use of English words mixed in with French speakers- in songs it quite often occurs.
For example, in M.C. Solaar's La Vie est Belle , he uses English words and makes them into French verbs- 'on veut me killer'- killer- to kill (tuer normally), or 'shooter' (to shoot).
More Examples of Franglais:
Je n'ai pas de money. (I don't have money)
C'est cool to use franglais.
Franglais and Frenglish are very informal. They are used among youth most commonly, and are inappropriate for formal or school-related usage, but can be fun and practical for people who are learning a foreign language, but are not fluent.
For a more complete history of Franglais, visit: