Create a new message in "Messaging" app :
- keep your finger on the comma (,) until a wheel is displayed ,
- slide your finger on this wheel (settings options are displayed),
- tap on "Languages",
- tap on "ADD KEYBOARD",
- select one or several languages in the list, if needed, and set your parameters,
- tap on "OK" or "Add" or "DONE",
- keep your finger on a language to place it according to your needs,
- tap on  once or twice to come back to the message.*

* To switch from a language to another one, touch the spacebar for 2 seconds.