diff --git a/bip39-standalone.html b/bip39-standalone.html
index b062b2e..6125ce3 100644
--- a/bip39-standalone.html
+++ b/bip39-standalone.html
@@ -22900,6 +22900,7 @@ WORDLISTS = {
     function findPhraseErrors(phrase) {
         // TODO make this right
         // Preprocess the words
+        phrase = mnemonic.normalizeString(phrase);
         var parts = phrase.split(" ");
         var proper = [];
         for (var i=0; i<parts.length; i++) {
diff --git a/src/js/index.js b/src/js/index.js
index d6f752d..5b8aedb 100644
--- a/src/js/index.js
+++ b/src/js/index.js
@@ -199,6 +199,7 @@
     function findPhraseErrors(phrase) {
         // TODO make this right
         // Preprocess the words
+        phrase = mnemonic.normalizeString(phrase);
         var parts = phrase.split(" ");
         var proper = [];
         for (var i=0; i<parts.length; i++) {