Italian interjections are characterized according to their morphological form:

• interiezioni proprie (proper interjections), so-called because they function only as interjections:

ah!, eh!, oh!, ahi!, ehi!, ohi!, mah!, urrà!, ahimè!, ohimè!

One characteristic typical of many proper interjections is that of changing meaning according to the context and intonation with which they are pronounced. For example, ah!

can express pain (Ah, che terribile notizia!), anger or indignation (Ah, traditore! così ripaghi la fiducia che ti ho dato!), or wonder or surprise (Ah, sei tu!). If repeated (ah! ah!), the interjection reproduces the sound of laughter, especially ironic or mocking. Similarly, eh! may indicate a reprimand or disapproval (Eh! Non è mica bello quello che hai fatto!), resignation (Eh! Mi creda, non so più a chi rivolgermi.) or can be used to seek the consent of the interlocutor (Eh? Che glie ne pare di questo quadro?). If pronounced with a questioning tone and prolonged sound eh! is used colloquially to respond to someone who has called or to indicate that you did not understand something (Eh? Puoi ripetere per favore?).

• interiezioni improprie (improper interjections), so-called because they are other parts of speech (nouns, adjectives, adverbs, verbs) functioning as an interjection:

coraggio!, peccato!, animo!, bravo!, giusto!, zitto!, bene!, presto!, via!, fuori!, evviva!, viva!, basta!

As for their meaning, they can express an order (basta!, zitto!, finiscila!), an exhortation (dai!, su!, coraggio!), a judgment of appreciation or criticism (bravo!, male!, vergogna!), or an expletive (peccato!, accidenti!, maledizione!). Some improper interjections can be used as expressions of courtesy (auguri!, congratulazioni!), as greetings or farewells (ciao!, arrivederci!, buonanotte!) or to attract the attention of the listener: senta!, scusi!, pronto?

• locuzioni interiettive (interjectional phrases) or locuzioni esclamative (exclamatory phrases), so-called because they are formed by groups of words or complete sentences:

Dio mio!, Santo cielo!, Per amor del cielo!, Povero me!, Per carità!, Dio ce ne liberi!

• Voci onomatopeiche (onomatopoeic noises) can also resemble interjections and are expressions that are able to reproduce or imitate, through the interplay of vowels and consonants, particular sounds or noises. So tic-tac indicates the beat of a clock, din-don the chime of a bell, patatrac the sound of something falling, eccì a sneeze, miao the meow of a cat, bau-bau a dog's barking.

Three types of expressions can be distinguished that are used to imitate noises in nature, and that are otherwise integrated into the Italian language:

• imitazioni non linguistiche (non-linguistc imitations) (for example, the reproduction of a train noise made by an impersonator), cannot be represented using phonemes or graphemes; in this case there is no linguistic integration.

• onomatopee semplici (simple onomatopoeia), which reproduce sound through the use of phonemes (in speech) or graphemes (in writing): plin, sdong, crac, tic-tac. In the case of simple onomatopoeia, integration into the linguistic system is minimal, since they are not equivalent to any of the traditional parts of speech and are usually included in speech without syntactic links with the rest of the sentence.

• the highest degree of integration into the Italian lexicon is found in onomatopee derivate (derived onomatopoeia), which are derived from onomatopee semplici (simple onomatopoeia) by adding a suffix (miao » miagolare). Derived onomatopoeia are classified morphologically (nouns, such as tintinnio, or verbs, such as tintinnare) and as such can establish grammatical links with the rest of the sentence:

Sentiva un miagolio insistente provenire dall'appartamento accanto.