Principal parts of verbs
All verb forms in these many combinations of person, number, tense, mood and voice (as well as forms we will learn later, such as infinitives and participles), are formed using the verb’s principal parts.
English verbs have a system of principal parts, too, although native speakers may not think about them that way. In English, the principal parts can include the present tense, the past tense, and the past participle: for example, play, played, played; swim, swam, swum; go, went, gone; do, did, done.
Latin verbs have up to four principal parts. For some verbs, not all parts exist, and so those verbs do not have the forms made from the missing principal part. In a glossary or a lexicon, Latin verbs are listed according to the first principal part, and so if you are looking a verb up you will need to be able to move from a verb form made from any principal part to its first principal part in order to find it in the lexicon. This need to move from form to part as well as from part to form is why memorizing principal parts is an important practice for learning Latin.
Forms of prinicipal parts
Two of the principal parts, the first and third, are finite verbs in a first person singular form (“I”) of the indicative mood. We’ll use them to find the stems we can modify with endings to create finite verb forms. The other two are forms of the verb we’ll learn to use in following chapters.
- The first principal part is the first person singular in the present active indicative (or the present passive indicative if active forms do not exist).
- The second principal is the present infinitive. (We’ll begin learning about uses of the infinitive in units 2 and 3.) You’ll look at the second principal part to find what set of endings to use with a stem.
- The third principal part is the first person singular in the perfect active indicative. If the verb has no active forms, it has no third principal part.
- The fourth principal part is the perfect passive participle. A participle has gender, case, and number as well as tense and voice. Latin textbooks and lexicons or dictionaries may follow one of two conventions, giving this form in either the masculine nominitive singular with the ending -us or the neuter nominative singular with them ending -um. We’ll learn in this unit how to use it create perfect passive forms.
Verb conjugations
Latin verbs are organized into four conjugations, a grouping where they share common endings. To find what conjugation a verb belongs to, look at the second principal part. In regular verbs, it will have one of four possible endings corresponding to the four conjugations.
- āre : first conjugation
- ēre : second conjugation
- ĕre: third conjugation
- īre: fourth conjugation
Examples of principal parts
Principal parts are listed in order, 1-4. Memorize these the principal parts of these thirteen common verbs that you will see repeatedly in reading Hyginus.
- amō, amāre, amāvī, amātus - to love
- audiō, audīre, audīvī, audītus - to hear
- capiō, capĕre, cēpī, captus - to take, seize
- dō, dāre, dedī, datus - to give
- dūcō, dūcĕre, dūxī, ductus - to lead
- faciō, facĕre, fēcī, factus - to make, do
- fugiō, fugĕre, fūgī, fugitus - to flee
- habeō, habēre, habuī, habitus - to have
- interficiō, interficĕre, interfēcī, interfectus - to kill
- mittō, mittĕre, mīsī, missus - to send
- sum, esse, fuī, futūrus - to be (irregular)
- veniō, venīre, vēnī, ventus - to come
- videō, vidēre, vīdī, visus - to see
Looking for patterns
As you learn principal parts, you should practice noticing patterns and then using those patterns to help you recognize, retrieve, use, and even take an educated guess at, a principal part.
Two good examples from your unit 1 vocabulary list are amō and audiō. Regular nouns of the first conjugation will change in exactly the same ways as amō. Drop the -āre ending from the second principal part, and you can reliably produce the others by add -ō to create the first part, -āvī to create the third part and -ātus for the fourth part.
Similarly, for regular verbs of the fourth conjugation, drop the -īre ending from the second part, and add -iō for the first part, -īvī for the second part, and -ītus for the fourth part.