A mobile device comprises a keypad comprising a plurality of keys for text entry into a text based application. Each key may represent at least two alpha numeric characters. A word layer disambiguation engine generates a list of textonyms for each of a sequence of words entered via user activation of the keys. A phrase layer disambiguation engine selects a single selected one of the textonyms for each word in the sequence of words. The selected one of the textonyms may be the textonym that meets selection criteria that is a function of one of : i) the word entered by the user prior to the textonym; ii) the word entered by the user following the textonym; iii) an identification of an application into which the user is entering the words,- and iv) identification of a recipient to which the words will be sent.