When you are learning a language, you tend to pay attention to what people say (unless you are tuning it out). I don't know about you, but when I hear a word for the first time, I know it's a first and put a mental asterisk next to it. Often, I just say, "Hey, I have never heard that word. What does it mean?" But much of the time I can figure out what a word means just by the context.
Italians use a variety of suffixes. There are various reasons to use a suffix, and sometimes it's just a personal preference to give a little emphasis to the word. Suffixes may change according to the area of Italy, so be prepared to learn some new ones depending on where you go.
I still remember the first time I heard the suffix -uccio in Italian. Many years ago, I happened to be near Rome in a house where a group of young music students were making lunch. That was already very interesting to watch, of course. But it was summer, it was hot, and one of the girls said, Che calduccio! It stuck in my mind. Isn't the word for "hot" just caldo? That one I knew, or thought I did. Why does she say calduccio? And is it a noun or an adjective? I might have been too shy to ask about that word, but I never forgot it.
I also had to figure out that sometimes there's a fine line between adjectives and nouns, that che can mean "what," as in "What tremendous heat!" or "how," as in "How tremendously hot it is!"
In the following example, we can sense the enveloping positive heat with the suffix -uccio. So, -uccio isn't necessarily positive or negative, but it's a way of reinforcing the adjective and providing it with something personal.
Adding -uccio is a way of emphasizing the quantity, quality, or intensity of heat being felt. Caldo by itself might be felt as neutral, but adding the -uccio assures you that things are going to be cozy.
E io farò un bel calduccio.
And I will make some nice heat.
Caption 50, PIMPA S3 EP 5 Il signor Inverno
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Sometimes -uccio is a suffix of endearment.
I have been called tesoruccio (dear/little treasure) or amoruccio (dear/little love) in the past. Translated literally, it sounds very stilted in English but it is pretty common in Italian and is a kind of equivalent of "sweetheart," darling," or "honey." It just adds some endearment and is more personal.
Tesoruccio mio, ti prego, perdonami.
Little treasure of mine, I beg you to forgive me.
Caption 33, La Ladra EP. 4 - Una magica bionda - Part 12
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Sometimes -uccio is diminutive, such as in minimizing un difetto (a defect).
Quando si parla troppo bene delle persone, senza neanche trovargli un difettuccio... Significa essere innamorata, zia.
When you talk too positively about people, without finding even one teensy flaw... It means being in love, Aunt.
Captions 35-37, Il Commissario Manara S2EP12 - La donna senza volto - Part 1
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We can use the suffix -uccio for emphasis with the adverb male (bad, badly). It can mean something like "kind of badly," or "pretty badly."
Com'è andata l'audizione? -Maluccio.
How did the audition go? -Pretty badly.
If the audition had gone really badly, the person might have answered: Male male, malissimo, or molto male.
There are lots of suffixes Italians use all the time, such as "-etto," "ino," "one," but It's impossible to predict, right off the bat, which suffixes go with which adjectives or nouns. You just have to listen a lot and adopt the ones that stick.
For more about parole alternate (modified or altered words) see this lesson.