Predicate words perform the same function in Latin as they do in English; they modify or describe a subject. The key to recognizing and translating predicate words in Latin lies in equating the subject and the predicate. Recall that words that modify nouns in Latin must agree in case, number, and gender. The same is true for predicate words; they must agree with the subject they describe in case number and gender similar to adjectives that modifying nouns. However, with the case of predicate words, the predicate does not need to be near to the subject as with a noun-adjective combination. Like English, a linking verb often separates the subject and its predicate. For example:
Julia est puella pulchra. (Julia is a beautiful girl.)
Illi viri sunt alti. (Those men are tall.)
Caesar erat validus. (Caesar was powerful.)
Notice three concepts in these examples. First, every subject (Julia, viri, Caesar) agrees with its predicate (puella, alti, validus) in case, number and gender. Second, notice that linking verbs (est, sunt, erat) separate the predicates from the subjects. Third, in the first example, the adjective “pulchra” agrees with the predicate (puella) it modifies in case, number, and gender.
Seeing three words in the nominative case can confuse the elementary Latin student because he or she has been taught to use the nominative case for the subject of a sentence only. Remember that predicate words are often equated with the subject of a sentence and therefore must agree in case, number, and gender. In fact, it would be just as valid to translate the three sentences above as:
A beautiful girl is Julia.
Tall are those men.
Powerful was Caesar.
These translations do not follow proper English grammar but they still convey the same sentiments.