vi: modify phoneme y@

phsource/ph_vietnam

@@ -563,11 +563,25 @@ endphoneme
 
 phoneme y@
   vwl  starttype #i  endtype #@
-  IF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordEnd) THEN
+  IF nextPhW(p) THEN
+	length 123
+  ELIF nextPhW(t[) THEN
+	length 123
+  ELIF nextPhW(c) THEN
+	length 139
+  ELIF nextPhW(m) THEN
+	length 127
+  ELIF nextPhW(n) THEN
+	length 180
+  ELIF nextPhW(N) THEN
+	length 156
+  ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordEnd) THEN
 	length 240
-	ELSE
+  ELIF thisPh(isFirstVowel) AND thisPh(isFinalVowel) AND thisPh(isWordStart) THEN
+	length 240
+  ELSE
 	length 200
-	ENDIF
+  ENDIF
   //FMT(vdiph2/y-y#)
   FMT(vietnam/y@)
 endphoneme