Why you don't recognise words you know
You know non, you know lo, you know so. What arrives in your ear is still something you cannot place: [nonloˈsɔ] — one single sound with one single beat, right at the end.
This is not mumbling. Small words like non, lo, ci and mi carry no accent of their own and lean on the next stressed word. The word boundaries audibly disappear.
English does this too — turn it off comes out as tur-ni-toff. So the linking itself is not new to you. What is new is that Italian links without shrinking anything: every little word keeps its full vowel.
Five groups to listen into
Non lo so.
[[nonloˈsɔ]]
I don't know.
Three words, one accent.
Non ce l'ho.
[[nontʃeˈlɔ]]
I don't have it.
Non ci credo.
[[nontʃiˈkreːdo]]
I don't believe it.
Ci vediamo.
[[tʃiveˈdjaːmo]]
See you.
Mi dispiace.
[[midisˈpjaːtʃe]]
I'm sorry.
The speech group
The gruppo ritmico is the unit of spoken Italian, not the word. It consists of one stressed content word plus the small words that lean on it: articles, prepositions, pronouns, the negation.
Where the borders lie
Non me l'ha detto nessuno.
[[nonmelaˈdetto nesˈsuːno]]
Nobody told me.
Two groups, two accents.
Quando torni, ti chiamo.
[[kwandoˈtorni tiˈkjaːmo]]
When you get back, I'll call you.
Ho un appuntamento alle tre.
[[ounappuntaˈmento alleˈtre]]
I have an appointment at three.
What happens at the word boundaries
Inside a group there are no clean word boundaries. Two things happen all the time as soon as there is no pause in between.
Vowels that meet are spoken in one go, with no break.
A consonant at the end of a word already belongs to the next syllable.
Linking in whole sentences
Che ora è?
[[keˈoːra ˈɛ]]
What time is it?
che and ora meet with no break.
Un altro caffè?
[[uˈnaltro kafˈfɛ]]
Another coffee?
The n of un slides onto altro: u-naltro.
Why your Italian sounds different
English squeezes unstressed syllables: vowels collapse into a colourless [ə], and small words shrink (and to [n], to to [tə]). Italian lets every vowel keep its full colour, stressed or not. In Non lo so the danger is not the so but the non and the lo: English hands them to the schwa and you get [nənləˈso] instead of [nonloˈsɔ].
With and without linking
Non lo so.
[[nonloˈsɔ]]
I don't know.
linked, full vowels — this is what it really sounds like
Non. Lo. So.
[[ˈnon ˈlo ˈsɔ]]
I don't know.
separated, every word stressed — sounds like dictation
telefono
[[teˈlɛːfono]]
telephone
all four vowels full
telefono
[[teˈlɛːfonə]]
telephone
last syllable murmured — the English schwa creeping in