Ubuntu – How to turn on phonetic typing for Tamil

Unfortunately, the various packages (e.g. wcatalan, wbritish-large wbritish-small, …) don't follow a pattern so

 apt-get install words-\*

or similar will not work. Typing /usr/share/dict into the search box of Software Center appears to yield all the wordlists, but I don't know if that is exhaustive.

If you want spell checking without the wordlists,

 sudo apt-get install aspell-\*

will pull in the (larger set) of spell checkers which work on a larger set of languages but cannot yield the wordlist used to compile them.

Be forewarned, given the way the wordlists were generated (cf. Steve Johnson CACM v28 1985) from words and proper nouns actually encountered in documents, the extra words might not be obviously jargon or proper to a non-native speaker)

Looks like Tamil support made it into 12.04 or even earlier. Though not everything is completely translated. I would recommend you get in contact with the localization team if you can help them out translating. Translating dialogues isn't very difficult, I have done some translations myself a few years ago for my language.

Last activity for Tabuntu on its sourceforge project page was logged 5 years ago. I consider that project abandoned. However there is an Ubuntu Tamil Team and a group on Launchpad. They seem to have plans for 12.04, I suggest you get in contact with them via IRC or Email. Ask them about the status of Tamil support in Ubuntu and ask yourself what can be done to improve the current status.