How does one know whether it means "The girls are happy" or "They are happy girls"?
Maybe if you think like Yoda you can get the idea of what to put. Allow me to explain: Kirini = happy (plural) Riñi = girls Issi = (they) are
So 'Riñi kirini issi' = "girls happy (they) are", which sounds like something Yoda would say for the "girls are happy"
To say "they are happy girls" Yoda would phrase it as "happy girls (they) are", so = 'Kirini riñi issi'
I know this is far from an official method for what you are asking, but hey, if it looks stupid but it works, then it ain't stupid.