On grammatical class:

cai
attitudinal: strong intensity attitude modifier.
cu'i
attitudinal: neutral scalar attitude modifier.
pei
attitudinal: attitudinal question; how do you feel about it? with what intensity?.
ru'e
attitudinal: weak intensity attitude modifier.
sai
attitudinal: moderate intensity attitude modifier.
dai'i
attitudinal modifier: supposed emotion - factual emotion
ne'e
polar opposite scalar negator; equivalent to {to'e} but in selma'o CAI
ni'au
attitudinal: 'how do you do?'
dau'i
attitudinal: equal intensity attitudinal relativizer
mau'i
attitudinal: stronger intensity attitudinal relativizer
me'ai
attitudinal: weaker intensity attitudinal relativizer

In definition:

cmavrcai
x1 is the selma'o "CAI".