Latin is a heavily inflected language with largely free word order. Nouns are inflected for number and case; pronouns and adjectives (including participles) are inflected for number, case, and gender; and verbs are inflected for person, number, tense, aspect, voice, and mood. The inflections are often changes in the ending of a word, but can be more complicated, especially with verbs.
Thus verbs can take any of over 100 different endings to express different meanings, for example regō "I rule", regor "I am ruled", regere "to rule", regī "to be ruled". Most verbal forms consist of a single word, but some tenses are formed from part of the verb sum "I am" added to a participle; for example, ductus sum "I was led" or ductūrus est "he is going to lead".