diff --git a/_layouts/default.html b/_layouts/default.html
index af0f525..5000399 100644
--- a/_layouts/default.html
+++ b/_layouts/default.html
@@ -47,6 +47,11 @@
             <meta itemprop="keywords" content="{{ page.tags | join: ',' }}" />
             <meta itemprop="dateCreated" content="{{ page.created | date: '%Y-%m-%d' }}" />
             <meta itemprop="dateModified" content="{{ page.updated | date: '%Y-%m-%d' }}" />
+            {% if page.language == 'de' %}
+                <meta itemprop="inLanguage" content="de" />
+            {% else %}
+                <meta itemprop="inLanguage" content="en" />
+            {% endif %}
             <section id="main_content" itemprop="articleBody">
                 {% if page.toc %}
                     <ul data-toc="#main_content"></ul>