How tho know wich keys have no text?

I have a lot of pages on http://busimatch.com and a lot of keys that are not connected to text.
How can i know wich keys have no text, or have i to look to each page?

Also sometimes i change keys, and later the keys are not translated.
What can be the problem?

Didier
 

 Do you mean you have a lot of language keys which are not used or have no translations? Do you have these keys already in your database?

Yes, i want to know wich keys have not text on my website.
It's possible in one way or another to know all the keys in the
database that have no text connected? 

I thought dat keys are only in Lang file.... 

Have you been editing your keys by directly changing the lang file in the lang folder?

If so, then that is the wrong way to do it, and would explain why your loosing keys you have already translated.

 SELECT * FROM `sys_localization_strings` WHERE `String` = ''

or

SELECT * FROM `sys_localization_keys` WHERE `Key` = ''