Verbs in Latin are defined by tense, mood, voice, person and number.
Tense: A verb's tense indicates in what time the action it describes is occurring.
Present tense describes an action that is occurring now at the present time. (For example, I see indicates that I am seeing in the present time.)
Mood: The mood of a verb indicates the form a verb takes on in order to reflect the way in which the speaker conceives of the action. There are 5 moods in Latin: Indicative, Infinitive, Imperative, Subjunctive, and Participle.
Indicative Mood: The indicative mood is used in simple statements of fact; it is used when the speaker wishes to be a detached observer who is merely stating a fact to someone.
In the sentence "The boy rode his bicycle down the street," the speaker is merely offering a statement of the fact that the boy did indeed ride his bicycle down the street.
Infinitive Mood: The infinitive is, as its name suggests, without the boundary (ie, IN-FINITE) of a personal ending.
In English, this form of a verb is expressed with the preposition "to" + the verb. For example, the verb "to run" does not express who or how many is running; it merely expresses the sentiment of "to run."
Imperative Mood: The imperative mood is used to make commands. In English, this is expressed by the simple form of the verb.
For example, if one wants the girl to run away, he/she simply looks at her and says "RUN!" This expression in English is simply an order for whomever the speaker is looking at to run.
Subjunctive Mood: The subjunctive mood is used in Latin for a variety of reasons, all of which will be addressed in more detail. In origin, however, it was the mood used to express potential and uncertainty as to the completion of the action of the verb.
In English, we express this by means of auxiliary verbs. For example, "She might pass the test" expresses both the potential of the girl to pass the test and the speaker's uncertainly that she will do so.
Participle Mood: Participles are verbs that function both as nouns or adjectives AND verbs. They are divided in by tense and voice.
The present active participle in Latin is the English -ing participle; She is running through the forest.
The future active participle in Latin is translated by means of the auxiliaries "about to....: She is about to run through the forest.
The perfect passive participle is roughtly equivalent to the auxiliaries "having been" + the -ed participle in English; "She ran through the having-been-walked-through forest."
The future passive participle, also known as the gerundive, is usually expressed in English by the auxiliaries "must be" or "needs to be" + the -ed participle; She saw the needing-to-be-run-through forest.
NB: Latin is capable of expressing these sentiments where English cannot. We would never, for example, say " needing-to-be-run-through forest," but the versatility of Latin participles allows for this expression.
