smaji -sma- gismu

x1 (source) is quiet/silent/[still] at observation point x2 by standard x3.

See also kerlo, panpi, savru, tirna.

In notes:

kerlo
x1 is a/the ear [body-part] of x2; [metaphor: sensory apparatus, information gathering].
panpi
x1 is at peace with x2.
savru
x1 is a noise/din/clamor [sensory input without useful information] to x2 via sensory channel x3.
tirna
x1 hears x2 against background/noise x3; x2 is audible; (adjective:) x1 is aural.
cmato'a
t1 is a tone low in pitch/frequency from source t3.
lauble
r1=c1 sounds quiet/weak at observation point c2 by standard c3=t3.
tolylau
x1 is soft/quiet/making only a bit of noise, at observation point x2 by standard x3.
lu'ei (exp!)
convert a grammatical quotation to a tanru unit; x1 expresses/says the quoted text for audience x2 via expressive medium x3.