diff --git a/dictsource/vi_rules b/dictsource/vi_rules
index b4279e91..7e2ba50a 100644
--- a/dictsource/vi_rules
+++ b/dictsource/vi_rules
@@ -84,6 +84,7 @@ ỵ	ỵ
 .L03 ch nh
 .L04 a u ă â o ô á à ả ã ạ ù ú ủ ũ ụ ắ ằ ẳ ẵ ặ ấ ầ ẩ ẫ ậ ó ò ỏ õ ọ ố ồ ổ ỗ ộ ư ứ ừ ử ữ ự ơ ớ ờ ở ỡ ợ
 .L05 o ó ò ỏ õ ọ ô ố ồ ộ ỗ ổ
+
 .group b
         b          b
      _) b          _b
@@ -267,7 +268,13 @@ ỵ	ỵ
 .group q
         q          k
         q (_       k
-        qu         kw         //kw
+		qu         kw         //kw
+		quô         ku@
+        quồ         ku@2
+        quố         ku@3
+        quổ         ku@4
+        quỗ         ku@5
+        quộ         ku@6
         
  
         
@@ -1025,7 +1032,6 @@ ỵ	ỵ
         u (@       _^_EN
        // ua (L01    _^_EN
 ?2      u          u-        
-     t) u (A       u
  
 
 .group ù
diff --git a/phsource/ph_vietnam b/phsource/ph_vietnam
index 4d0b3ea3..68a17612 100644
--- a/phsource/ph_vietnam
+++ b/phsource/ph_vietnam
@@ -608,10 +608,36 @@ endphoneme
 
 phoneme w
   liquid
-  lengthmod 3
+  lengthmod 7
   starttype #u
   
   IF nextPh(isVowel) THEN
-    FMT(vnasal/u_n, 60)
+    NextVowelStarts
+      VowelStart(w/w@)
+      VowelStart(w/wa)
+      VowelStart(w/we)
+      VowelStart(w/wi)
+      VowelStart(w/wo)
+      VowelStart(w/wu)
+    EndSwitch
+
+    VowelEnding(w/xw, -30)
+	IF nextPh(isVowel) AND prevPhW(t[) THEN
+		FMT(vnasal/u_n, 60)
+	ENDIF
+    IF prevPhW(isNasal) THEN
+      FMT(w/w)
+    ELSEIF prevPhW(h) THEN
+      // none,  [hw]
+    ELSE
+      FMT(w/_w)
+    ENDIF
+  ELSE
+    // no vowel follows
+    Vowelout len=50
+    IF prevPh(#i) THEN
+      FMT(w/iw_)
+    ENDIF
+    FMT(w/w_)
   ENDIF
 endphoneme
\ No newline at end of file