looking for an application that can replace Thai script and Latin characters

for example; a thai word would be replace with English keys and vice versa

instead of using the Thai keys to type "water" I simply type "ohe" and one click on the replace button would produce "water" in Thai script

does it exists? (or do I have to make my own?)

But it's faster to use the shortcuts for swithing... like Ctrl+Shift น้ำ Ctrl+Shift or whatever you have set up...

Martin