Changing language button

Hello. Does anyone know how to make a changing language button? Thanks

Do you mean a switch to allow members to go from one language to another?

Yes. How can I do it?

Well, if you mean the built-in languages features, in the Admin panel check out Settings|Language Settings.  There's a section where you can create a new language and you'll get more tiny flags at the top of your pages where users can click to switch languages.

Now, you have to have the language keys defined for each language you add.  You can buy some language packs that have the default keys translated.  Otherwise, and for other languages or custom keys you may add to your site (new menus and profile settings, etc.) then you'll have to define your own.

At the bottom of the language settings menu, you can browse or search for keys by name.  Keys by convention start with an underbar "_" or 2 "__".  Using the create new key or editing existing ones, you can fill in the translation for each languages.  This is also where you edit some of the starndard page contents like "About Us," FAQ, and Terms. 

Now, this only translates standard stuff on your site, not user content, say on the forums.  If you're looking for automatic translation of that stuff, you can look into Google or Bing for their language toolbars that use their engines to translate pages.  Of course, these translations are notoriously still lacking.  I have not tried integrating these with Dolphin either.