Tai Viet input method using the phonetic key sequence with the Tai Son La keyboard layout.
The phonetic key sequence means that you type a syllable in this order:
C W? V v? F? T?
where
C is an initial consonant,
W is a label for labializing C ('ꪫ'),
V is a vowel (V1:prefix, V2:combining, or V3:postfix),
v is the second vowel of a digraph vowel
(in the case that V is 'ꪹ' and v is 'ꪸ', 'ꪷ', or 'ꪱ'),
F is a final consonant,
T is a tone-mark (spacing or combining).
You can type special symbols by these keys:
'$' -> 'ꫛ'
'#' -> 'ꫜ'
'%' -> 'ꫝ'
'!' -> '꫞'
'@' -> '꫟'