Do all the | default in the language files and access lang strings in index using simple variables

_includes/lang

@@ -1,2 +1,4 @@
 {% assign lang = site.data.lang.[include.lang].[include.for] %}
-{% assign en = site.data.lang.en.[include.for] %}
+{% assign en = site.data.lang.en.[include.for] %}
+
+{% include langs/{{include.for}} lang=lang en=en %}