[Typo3] extension with language specific content

[T.Joga]

Hello! I am wondering how to make simple extension where content is 
separated by the language. Currently I have simple "test"-extension with 
one "text-area" and "string-input"-field. .. it works, at least somehow.

The problem is that all translated content is shown on the same 
list/page and this what I dont want.

I am quite lost in here, this is propably simple, but I dont get where I 
should put *something* in the extension code(class.tx_test.p1.php) to 
get this to work.
I assume that this is the line which gets data from the db:

$res = $this->pi_exec_query('tx_test_test');

I tried this;

$this->query = "AND sys_language_uid='1'";
$res = $this->pi_exec_query('tx_test_test');

..surprise, it didnt work..
There is great language support in the "tt_news"-extension, but its a 
bit too overkill example for my current knowhow of typo!