else if → elseif

_layouts/default.html

@@ -9,7 +9,7 @@ layout: base
 {% if language == "_it" %}
 	{% assign language = "it" %}
 	{% assign links = site.it | sort: "idx" %}
-{% else if language == "_de" %}
+{% elseif language == "_de" %}
 	{% assign language = "de" %}
 	{% assign links = site.de | sort: "idx" %}
 {% else %}