How to make a Language KEY?

I want to have a language switcher to the header and the text will be ''Language''.

But if the user change the language, how can i make this text ''Language'' change to other language.

I already add a language key string to admin panel. But how to add that to the template so it get the right language string for each language?

In a template you use <bx_text:_language_key /> where _language_key is the actual name of your key.

In PHP script you use the command _t('_language_key');

Thank you! That work fine in the template.

 I almost give up here again.