PARTS OF SPEECH (Parolpartoj).
95. There are nine parts of speech in Esperanto, as found in most other languages, viz., the Article (Artikolo), Noun (Substantivo), Pronoun (Pronomo), Adjective (Adjektivo), Verb (Verbo), Adverb (Adverbo), Preposition (Prepozicio), Conjunction (Konjunkcio), Interjection (Interjekcio).
Nouns, derived adjectives and adverbs, and verbs have distinctive terminations. If a word ends in -O, it is a noun; if in -A, an adjective; if in -E, an adverb; if in -I, -U, -AS, -IS, -OS, or -US, a verb. If it ends in -N, it is in the accusative case, and if in -J, it is plural.
Examples.—Domo = a house. Facila = easy. Feliĉe = happily. Doni = to give (Infinitive). Batu lin = beat him (Imperative and Accusative). Mi vidas la homojn = I see the men (Present tense and Accusative plural). Vi diris = you said (Past tense). Ni iros = we shall go (Future tense). Se ili estus bonaj = If they were good (Conditional mood and plural adjective).