You can add non-sense words to the T9 dictionary. For example, in T9, try typing 366227. You will get "donacs" or "donacr". Suppose you don't want either of those. Erase them. Go to "abc" mode and enter "foobar". Leave the cursor sitting immediately to the right of "r". Change back to T9. Press "Next". The "foobar" will be highlighted. Press "Space". Now "foobar" has been added to the dictionary. Try it out. While still in T9, type 366227. You will still get "donacs" but press "Next" a couple times and you'll get "foobar".