There is a small problem with vntelex.el input method. That is when you type "aff", the result should be "af" instead of "aff".
My emacs version is GNU Emacs 23.1.1 (i686-pc-linux-gnu, GTK+ Version 2.18.7) of 2010-03-16 on gen2pc.
I made a patch here, hope you guys will fix it soon. It's quite annoying when typing in Vietnamese while this bug still exists.
*** /usr/share/emacs/23.1/leim/quail/vntelex.el.old 2010-04-05 04:22:53.000000000 +0700
--- /usr/share/emacs/23.1/leim/quail/vntelex.el 2010-04-05 04:11:55.000000000 +0700
***************
*** 285,291 ****
("Dd" ?Đ)
;("$$" ?₫) ; U+20AB DONG SIGN (#### check)
! ("aff" ["aff"])
("AFF" ["AF"])
("Aff" ["Af"])
("ass" ["as"])
--- 285,291 ----
("Dd" ?Đ)
;("$$" ?₫) ; U+20AB DONG SIGN (#### check)
! ("aff" ["af"])
("AFF" ["AF"])
("Aff" ["Af"])
("ass" ["as"])