The last important rule of the Thai script is the class change. This operation will transform a low consonant in high consonant.

Any consonant preceded by   is transformed in high consonant.

To this rule there are 4 important exception : 4 words very used are transformed with the consonant  .


Exemple :

nuu yoot laai mai
Mouse / Rat Stop Several

Exception :

yaa yuu yaang yaak
Don't Is / Stay manner wish