For many Italian language speakers—even for those whom Italian is their madrelingua—the phrase parti del discorso might seem foreign. English speakers know the concept as "parts of speech," but it's probably a term vaguely remembered from grade school grammar.
A part of speech (whether Italian or English) is a "linguistic category of words generally defined by the syntactic or morphological behavior of the lexical item in question." If that definition intrigues you, then an introduction to Italian linguistics might be a jumping off point. Suffice it to say that linguists have developed a classification system that groups specific types of words according to their roles.
For anyone whose primary goal is to speak like an Italian, perhaps it's enough to be able to identify each of the parti del discorso to facilitate learning the language. By tradition, grammarians recognize nine parts of speech in Italian: sostantivo, verbo, aggettivo, articolo, avverbio, preposizione, pronome, congiunzione, and interiezione. Below is a description of each category with examples.
Noun / Sostantivo
A noun (sostantivo) indicates persons, animals, things, qualities, or phenomena. "Things" can also be concepts, ideas, feelings, and actions. A noun can be concrete (automobile, formaggio) or abstract (libertà, politica, percezione). A noun can also be common (cane, scienza, fiume, amore), proper (Regina, Napoli, Italia, Arno), or collective (famiglia, classe, grappolo). Nouns such as purosangue, copriletto, and bassopiano are called compound nouns and are formed when combining two or more words. In Italian, the gender of a noun can be male or female. Foreign nouns, when used in Italian, usually keep the same gender as the language of origin.
Verb / Verbo
A verb (verbo) denotes action (portare, leggere), circumstance (decomporsi, scintillare), or state of being (esistere, vivere, stare).
Adjective / Aggettivo
An adjective (aggettivo) describes, modifies, or qualifies a noun: la casa bianca, il ponte vecchio, la ragazza americana, il bello zio. In Italian, there are several classes of adjectives, including: demonstrative adjectives (aggettivi dimostrativi), possessive adjectives (aggettivi possessivi), indefinite adjectives (aggettivi indefiniti), numerical adjectives (aggettivi numerali), and degree of comparison adjectives (gradi dell'aggettivo).
Article / Articolo
An article (articolo) is a word that combines with a noun to indicate the gender and number of that noun. A distinction is usually made between definite articles (articoli determinativi), indefinite articles (articoli indeterminativi), and partitive articles (articoli partitivi).
Adverb / Avverbio
An adverb (avverbio) is a word that modifies a verb, an adjective, or another adverb. Adverb types include manner (meravigliosamente, disastrosamente), time (ancora, sempre, ieri), place (laggiù, fuori, intorno), quantity (molto, niente, parecchio), frequency (raramente, regolarmente), judgment (certamente, neanche, eventualmente), and interrogative (perché?, dove?).
Pronoun / Pronome
A pronoun (pronome) is a word that refers to or substitutes for a noun. There are several types of pronouns, including personal subject pronouns (pronomi personali soggetto), direct object pronouns (pronomi diretti), indirect object pronouns (pronomi indiretti), reflexive pronouns (pronomi riflessivi), possessive pronouns (pronomi possessivi), interrogative pronouns (pronomi interrogativi), demonstrative pronouns (pronomi dimostrativi), and the particle ne (particella ne).
Conjunction / Congiunzione
A conjunction (congiunzione) is the part of speech that joins two words, sentences, phrases or clauses together, such as: quando, sebbene, anche se, and nonostante. Italian conjunctions can be separated into two classes: coordinating conjunctions (congiunzioni coordinative) and subordinating conjunctions (congiunzioni subordinative).
Interjection / Interiezione
An interjection (interiezione) is an exclamation that expresses an improvisational emotional state: ah! eh! ahimè! boh! coraggio! bravo! There are many types of interjections based on their form and function.