Latin verbs have many forms throughout the language’s four conjugations. Each conjugation has its own little quirks, proving once again that Latin is a language of exceptions. Also once again, memorization is a key to success in a Latin language program of study.
Most English programs teach that English verbs have three principal parts. However, most Latin programs teach that Latin verbs have four. Really, they are the same as in English, but the infinitive form of the verb becomes the second principal part, the present perfect form becomes the third, and the past participle is the fourth. Here is a breakdown of the four principal parts for the verb “amo," a common word in Latin programs.
amo (first-person singular present active indicative)
amare (singular present active indicative infinitive)
amavi (first-person singular (present) perfect active indicative)
amatum (nominative perfect (past) passive participle)
The problem for Latin students begins when the first conjugation is introduced. All of Latin’s first conjugation verbs follow the –o, –are, –avi, –atum principal part pattern giving students little incentive to memorize a verb’s principal parts. After all, every verb they have encountered up until now belongs to the first conjugation and all of them follow a very regular pattern.
The situation becomes more complicated at the introduction of the second conjugation. Luckily, second conjugation verbs follow the regular pattern –o, -ere, -ui, -itum such as the common verb moneo, monere, monui, monitum. Still, most Latin students tend to memorize to which conjugation a verb belongs rather than the formation of principal parts.
Disaster strikes at the third conjugation. You see, second and third conjugation verbs have nearly an identical second principal part form; they both have an –ere ending for the singular present active indicative infinitive. However, the first –e– is long in the second conjugation and short in the third. Many Latin programs make use of a macron over long vowels, but not all do.
The result is many Latin students forming third conjugation verbs (the future active indicative in particular) as if they belong to the second conjugation such as:
agabo (incorrect) agam (correct)
agabis (incorrect) ages (correct)
agabit (incorrect) aget (correct)
agabimus (incorrect) agemus (correct)
agabitis (incorrect) agetis (correct)
agabunt (incorrect) agent (correct)
Without an incentive to memorize the principal parts of a verb at the beginning of their Latin studies, many students find themselves having to revisit and rememorize earlier lessons. This is usually on top of the new material presented as the course moves on.