The Perfect Stem

The circumflected accents are used to mark the vowels' length.

The perfect stem is derived from the root in several ways:

1. With the characteristic –v- after a long vowel. The most verbs of the I and IV conjugations and some verbs of the II and III conjugations form their perfect stem with it:
 

Verb	Present stem	Perfect stem
amo, 1 to love audio, 4 to hear deleo, 2 to destroy cupio, 3 to long for	amâ- audî- delê- cupi-	amâv- audîv- delêv- cupîv-

2. With the characteristic –u- after consonants only. This characteristic replaces the thematic vowel of the verbs of the I, II and IV conjugations. A great part of the II conjugations verbs form their perfect stem in this way:
 

Verb	Present stem	Perfect stem
veto, 1 to forbid moneo, 2 to remind alo, 3 to nourish salio, 4 to jump	veta- mone- al- sali-	vetu- monu- alu- salu-

3. With the characteristic –s- after consonants only. It is used to form the perfect stem of many verbs of the III conjugations and of some verbs of the II and IV conjugations; the verbs of the I conjugation never form their perfect stem in this way. The characteristic –s- often brings for the changing of the preceding consonant:
 

Verb	Present stem	Sound changes	Perfect stem
maneo, 3 to remain  repo, 3 to crawl	manê- rep-	no changes	mans- reps-
duco, 3 to lead rego, 3 to rule traho, 3 to drag	duc- reg- trah-	c+s > x g+s > x h+s > x	dux- rex- trax-
scribo, 3 to write	scrib-	b+s > ps	scrips-
rideo, 2 to laugh mitto, 3 to send cedo, 3 to go sentio, 4 to feel	ride- mitt- ced- senti-	d+s > s tt+s >s d+s > ss t+s >s	ris- miss- cess- sens-

4. By reduplication of the first root consonant followed by the vowel e:
 

Verb	Present stem	Perfect stem
do, 1 to give cado, 3 to fall cano, 3 to sing	da- cad- can-	ded- cecid- cecin-

5. By reduplication of the first root syllable:
 

Verb	Present stem	Perfect stem
spondeo, 2 to promise mordeo, 2 to byte curro, 3 to run	sponde- morde- curr-	spopond- momord- cucurr-

6. By the lengthening of the root vowel and cutting away of the thematic vowel (if the verb belongs to the I, II or IV conjugation):
 

Verb	Present stem	Perfect stem
lavo, 1 to wash video, 2 to see lego, 3 to read venio, 4 to come	lava- vide- leg- veni-	lav- vid- leg- vên-

7. By the ablaut and lengthening of the root vowel:
 

Verb	Present stem	Perfect stem
ago, 3 to conduct capio, 3 to seize sido, 3 to sit down	ag- capi- sid-	êg- cêp- sêd-

8. By extracting an infixal –n- from the present stem:
 

Verb	Present stem	Perfect stem
vinco, 3 to vanquish	vinc-	vîc-

Note that some verbs have incorporated the infixal –n- of the present stem in the perfect stem also:
 

Verb	Present stem	Perfect stem
stringo, 3 to strain pango, 3 to fix	string- pang-	strinx- panx-

9. By applying several of the above transformations at once:
 

Verb	Present stem	Transformation	Perfect stem
tango, 3 to touch   pango, 3 to fix     sino, 3 to allow	tang-   pang-     sin-	reduplication and extraction of the infixal –n- ---,,--- extraction of the infixal –n- and ablaut with lengthening extraction of the infixal –n- and adding the characteristic –v-	tetig-   pepig- pêg-   siv-

10. Few verbs have identical present and perfect stems:
 

Verb	Present stem	Perfect stem
bibo, 3 to drink defendo, 3 to defend statuo, 3 to set up	bib- defend- statu-	bib- defend- statu-