a) The Verb Stem is reduplicated by prefixing the initial consonant with the following vowel or e; as,—
| currō, | Perfect | cu-currī. |
| poscō, | " | po-poscī. |
| pellō, | " | pe-pulī. |
NOTE 1.—Compounds, with the exception of dō, stō, sistō, discō, poscō, omit the reduplication. Thus: com-pulī, but re-poposcī.
NOTE 2.—Verbs beginning with sp or st retain both consonants in the reduplication, but drop s from the stem; as, spondeō, spo-pondī; stō, stetī.
b) The short vowel of the Verb Stem is lengthened; as, legō, lēgī; agō, ēgī. Note that ă by this process becomes ē.
c) The vowel of the Verb Stem is unchanged; as, vertō, vertī; minuō, minuī.
Formation of the Participial Stem.
[119]. The Perfect Passive Participle, from which the Participial Stem is derived by dropping -us, is formed:—
1. By adding -tus (sometimes to the Present Stem, sometimes to the Verb Stem); as,—
| amā-re, | Participle | amā-tus. |
| dēlē-re, | " | dēlē-tus, |
| audī-re, | " | audī-tus, |
| leg-ere, | " | lēc-tus, |
| scrīb-ere, | " | scrīp-tus, |
| sentī-re, | " | sēn-sus (for sent-tus). |
| caed-ere, | " | cae-sus (for caed-tus). |
a. Note that g, before t, becomes c (see [§ 8], 5); b becomes p; while dt or tt becomes ss, which is then often simplified to s ([§ 8], 2).