diff --git a/phsource/ph_vietnam b/phsource/ph_vietnam
index 49cfda3f..91f568fc 100644
--- a/phsource/ph_vietnam
+++ b/phsource/ph_vietnam
@@ -99,6 +99,8 @@ phoneme a:
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 333
   ELSE
 	length 180
   ENDIF
@@ -126,6 +128,8 @@ phoneme E
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 352
   ELSE
 	length 180
   ENDIF
@@ -152,6 +156,8 @@ phoneme e
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 324
   ELSE
 	length 180
   ENDIF
@@ -195,6 +201,8 @@ phoneme i
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 363
   ELSE
 	length 180
   ENDIF
@@ -224,6 +232,8 @@ phoneme O
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 331
   ELSE
 	length 180
   ENDIF
@@ -260,6 +270,8 @@ phoneme o
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 363
   ELSE
 	length 180
   ENDIF
@@ -286,6 +298,8 @@ phoneme u
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 333
   ELSE
 	length 180
   ENDIF
@@ -310,6 +324,8 @@ phoneme y
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 328
   ELSE
 	length 180
   ENDIF
@@ -362,6 +378,8 @@ phoneme @:
 	length 240
   ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
 	length 240
+  ELIF thisPh(isWordStart) AND thisPh(isWordEnd) THEN
+     length 333
   ELSE
 	length 180
   ENDIF