PyroCMS Language Tag to display the language code

Question

I'm using PyroCMS Pro 2.2.6. I created in a PyorCMS Stream a language field which I would like to use in my template to display the language code (en, de, fr, etc.):

I tried many different tags like:

{{ web_language }}
{{ web_language:name }}
{{ web_language:value }}
{{ web_language:key }}
{{ web_language:code }}

Only the first one worked and displayed the language value (English, Germany, etc.). Which tag can I use to display the language code?

BTW there seems to be missing the label above the radio buttons when you choose PyroCMS Language as field type.