a. The suffix v (u) is added to the verb-stem: as, vocá-v-í, audí-v-í; or to the root: as, son-u-í (soná-re, root SON), mon-u-í (moné-re, MON treated as a root).[1][The v-perfect is a form of uncertain origin peculiar to the Latin.]
NOTE: In a few verbs the vowel of the root is transposed and lengthened: as, strá-v-í (sternó, STAR), spré-v-í (spernó, SPAR).
b. The suffix s is added to the root: as, carp-s-í (CARP), téx-í (for tég-s-í, TEG).[2][The s-perfect is in origin an aorist. Thus,
díx-í (for dícs-í) corresponds to the Greek
aorist NOTE: The modifications of the present stem sometimes appear
in the perfect: as, fínx-í (FIG, present stem finge-), sánx-í (SAC, present stem sancí-).
c. The root is reduplicated by
prefixing the first consonant - generally with e, sometimes with the root-vowel: as, ce-cid-í (cadó, CAD), to-tond-í (tondeó, TOND).
NOTE: In fid-í (for fe-fid-í, find-ó),
scid-í (for sci-scid-í, scindó), the
reduplication has been lost, leaving merely the root.
d. The root vowel is lengthened, sometimes
with vowel change: as, lég-í (leg-=o), ém-í (em-ó), víd-í
(vid-e-ó), fúg-í (fug-i-ó), ég-í
(ag-ó).
e. Sometimes the perfect stem has the same
formation that appears in the present tense: as, vert-í (vert-ó), solv-í
(solv-ó).
f. Sometimes the perfect is formed from a
lost or imaginary stem: as, petí-v-í (as if from peti-ó, petí-re, PET).