diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6e0c91e..ba038b7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,7 @@
 - Fix responsive layout on dashboard
 - Fix presenter layout with embeds when messages are hidden
 - Fix missing stream for form submits
+- Fix unknown locales
 
 ## v2.0.0
 
diff --git a/assets/js/app.js b/assets/js/app.js
index 1bea850..a011769 100644
--- a/assets/js/app.js
+++ b/assets/js/app.js
@@ -21,9 +21,16 @@ import Split from "split-grid";
 import { TourGuideClient } from "@sjmc11/tourguidejs/src/Tour";
 window.moment = moment;
 
-const locale =
+const supportedLocales = ["en", "fr", "de", "es"];
+
+var locale =
   document.querySelector("html").getAttribute("lang") ||
   navigator.language.split("-")[0];
+
+if (!supportedLocales.includes(locale)) {
+  locale = "en";
+}
+
 window.moment.locale("en");
 window.moment.locale(locale);
 window.Alpine = Alpine;