Predictive text input is based on a built-in dictionary to which you can add new words.
Depending on the language and the length of the words, you may be able to add hundreds of words to the dictionary. The more phone memory you have, the more words you can add. To free your phone memory, delete photos, ringing tones, or other data in the phone memory.
Note: You cannot manually delete words that were added to your dictionary. When the dictionary is full, the most recent addition replaces the first.