A verb's voice shows the relationship between the subject and the action expressed by the verb. Latin has two voices: active and passive.

In the active voice, the subject of the clause performs the verb on something else (the object), e.g., "The girl sees the boy."

In the passive voice, the subject of the sentence receives the action of the verb, e.g., "The boy is seen by the girl."

The personal endings in the active voice are: -ō/-m, -s, -t, -mus, -tis, -nt.

The personal endings in the passive voice (present, imperfect, future) are: -r, -ris, -tur, -mur, -mini, -ntur.

In the perfect, pluperfect and future perfect, the passive voice is formed by the fourth principal part plus the proper forms of sum, esse. For the perfect tense, use the present forms of esse, for the pluperfect use the imperfect forms of esse, and for the future perfect use the future forms of esse. The fourth principal part, when used in a passive construction, acts as a first-second declension adjective and is declined accordingly.

As stated before, when the passive voice is used, the subject receives the action of the verb from another agent. This agent, when it is a person, is expressed by the preposition ā/ab plus the ablative case. This construction is called the ablative of personal agent. The ablative of cause is used without a preposition when the agent is not a person.

Examples:

• Active: Puella puerum videt. (The girl sees the boy.)

• Passive: Puer ā puellā vidētur. (The boy is seen by the girl.)

Puella takes ā and the ablative, as it is a personal agent.

• Active: Timor virum capit. (Fear seizes the man.)

• Passive: Vir timore capitur. (The man is seized by fear.)

Timore is ablative of cause.

• Active: Hostēs urbem oppugnābant. (The enemies were attacking the city.)

• Passive: Urbs ab hostibus oppūgnābātur. (The city was being attacked by the enemies.)

Deponent verbs

Some verbs are always passive in form, even though they have an active meaning. For example:

• filius agricolam sequitur - The son follows the farmer
• sol ortus est - The sun has risen
• agricolae hostes verentur - The farmers fear the enemies
• gladio usus sum - I used a sword

Some, called semi-deponent verbs, take on a passive form on only in the perfect. For example:

• colono confido - I trust the farmer
• colono confisus sum - I trusted the farmer

Note that some deponent and semi-deponent verbs take the accusative case (eg. vereor, vereri, veritus sum = I fear), some the ablative (eg. utor, uti, usus sum = I use) and some the dative (eg. confido, confidere, confisus sum = I trust). When you first encounter such a verb in Latin, be sure to remember the case of the object the verb is taking along with its spelling and meaning.