Thanks, it works perfect!
Could it be possible to change language words into a flag pictures?

One option is <img src ="$Locale.png" /> Or better yet is a php function that gives the right path

Or you use the class="$Locale" in your css file (with li.de-DE a for instance) to change the background of the href for link and hover

I've used a space in the code:

<img src ="themes/mytheme/images/$Locale .png" alt="$Title" />

And flag picture names are respectively "en_GB .png" & "lt_LT .png" - now works perfect.
Not sure why did'n work without a space - checked final html code and observed that $Locale argument wasn't grabbed...

Try putting curly brackets around your variable or else .png is read as a property or method for $Locale.

<img src ="themes/mytheme/images/{$Locale}.png" alt="$Title" />

Cheers yurigoul, your _config.php code worked for me, fixing this DB build error:

Unknown column 'SiteTree.Locale' in 'where clause'