Bro it is the same as English..... But "WA" can use in many forms
Pood = Speak
Wa = Said/say (normally "WA" can be use depends on which sound u using, it have the same meaning as "Scold". Scold = DA ......So it all depends on how u use it.)
example - Khun Wa phom chai mai? (Are u saying about me?) or Khun Da phom lor? (Are u scolding me)
If Wa in different sound means other things also can mixed with other words to form a sentence.....like bro ahsiam87 - Arai Wa? (what?

?)
Khao bork wa or Khao pood wa.... (he said that...)
Bork = Tell
Example......
Pood - Khun pood pasa Thai dai mai? ( Can u speak Thai language? )
Bork - "Phom yark bork khun Phom ruk ter jing jing" or "Mai yark bork khun" ( I want to tell u I really love u) or (don't want to tell u)
Wa - Khun kamlang WA phom yoo lor? ( Are u saying something about me? )
Hope this helps..maybe other bros have better explanation...
