This little poem is from Giuseppe Gatti's Sales Poetici, Proverbiales, et Iocosi, published in 1703.
Fortuna Vocor
Dixit Fortuna: si starem lege sub una
Et non mutarer, tunc non Fortuna vocarer.
The vocabulary is keyed to the DCC Latin Vocabulary list. All the words in this poem are on that list:
dīcō dīcere dīxī dictum: say; causam dicere, plead a case; diem dicere, appoint a day
et: and
fortūna -ae f.: fortune
lēx lēgis: f. law
mūtō -āre: change
nōn: not
sī: if
stō stāre stetī statum: stand
sub: under, close to (+acc. or abl.)
tum or tunc: then
ūnus -a -um: one
vocō -āre: call