diff --git a/index.js b/index.js
index 61581545..e93424b3 100644
--- a/index.js
+++ b/index.js
@@ -103,6 +103,7 @@ function is(x) {
         "Sip Sam", // Thai Transcription with space
         "тринадцять", // Ukrainian
         "تیرہ", // Urdu
+        "mười ba", // Vietnamese
         "tri ar ddeg", // Welsh
         "דרייַצן", // Yiddish,
         "דרייצן", // Yiddish (without diacritics),