Unlike English verbs with three principal parts, Latin has four principal parts, which must be memorized to properly conjugate the verb. In addition, saying the principal parts aloud as they are learned is essential to tell one conjugation from another.
One of the requirements of learning Latin is proper pronunciation. Pronouncing Latin aloud not only helps solidify concepts into memory, it is absolutely essential to identify to which conjugation a verb belongs. Latin has four conjugations, each with differences in the way verbs are formed. Particularly difficult is distinguishing second and third conjugation verbs because the second principal part of both is spelled the same. Only in a Latin textbook will the macron of the second conjugation reveal a second-conjugation verb. When speaking or listening to Latin, the only clue to a verb’s conjugation is its pronunciation.
Principal parts are forms of a verb which must be memorized so that a verb can be fully conjugated. In English, only three principal parts are necessary. For example, to form the six tenses of the verb to eat, the following principal parts exist:
eat (first person, singular, present, active, indicative)
ate (simple past tense)
eaten (past participle)
From these principal parts, all of the forms of the verb can be derived using standard rules.
Latin is similar except that an extra principal part is added between the first and second to indicate to which conjugation the verb belongs. The principal parts for the verb laudo (to praise, from which English gets the word laudatory) are:
laudo (as English, first person, singular, present, active, indicative)
laudare (the infinitive form of the verb, to praise)
laudavi (first person, singular, perfect, active, indicative)
laudatum (past participle)
Luckily, many Latin verbs follow an easily-remembered pattern. First conjugation verbs, like laudo, always follow the –o, –are, –avi, –atum pattern such as:
amo, amare, amavi, amatum (to love)
voco, vocare, vacavi, vocatum (to call)
ceno, cenare, cenavi, canatum (to dine)
As found in English, Latin has some irregular verbs in which the principal parts follow no recognizable pattern. For, example:
ago, agere, egi, actum (to do)
Irregular verb principal parts must be memorized when the word is first introduced in a student’s studies. Failure to do so will result in having to look up the word in the dictionary. However, if the word egi is used in a sentence, the student will find it difficult to find it in the dictionary since egi starts with an e and the root word starts with an a. In most Latin dictionaries, verbs are listed first by their root (first principal part) and then by the infinitive (second principal part) to indicate the conjugation.