diff --git a/phsource/ph_vietnam b/phsource/ph_vietnam
index 850a0929..f100c852 100644
--- a/phsource/ph_vietnam
+++ b/phsource/ph_vietnam
@@ -240,8 +240,8 @@ phoneme O
   ELSE
 	length 180
   ENDIF
-    FMT(vdiph2/o_oo) //vowel/oo)
-	//FMT(vietnam/O)
+    //FMT(vdiph2/o_oo) //vowel/oo)
+	FMT(vietnam/oo)
 endphoneme
 
 phoneme O+
diff --git a/phsource/vietnam/oo b/phsource/vietnam/oo
new file mode 100644
index 00000000..88093a70
Binary files /dev/null and b/phsource/vietnam/oo differ