Italians can remember fewer numbers.
When you try to remember something like a phone number you have to keep repeating it to yourself or it disappears. This is because the part of your working memory which remembers sounds can only hold those sounds for a few seconds.
Psychologists call that part of your brain the phonological store. Each time you recite the phone number to yourself you are putting those digits back into the store one by one (this is called the phonological loop). However, the phonological store only lasts a few seconds. If the number takes longer to recite than the store lasts, the final digits will have dropped out of memory before you can get to them to put them back in.
For example, if you hear or read the first 10 digits of pi after the decimal place and try to remember them, you will begin repeating them to yourself… one four one five nine two six five three five. It might take you five seconds to recite them. But, if your phonological store only lasts four seconds, the last couple of digits will drop out of your phonological store before you can articulate them to yourself. The first eight digits have been put back in the store (where they will each remain for another 4 seconds unless you once again renew them by articulating them again before they disappear), but the last two are gone.
Italians have longer words for numbers than we do in English. Most digits have two syllables. Those ten digits of pi would be: uno quattro uno cinque nove due seis cinque tre cinque. In this example that would mean about 18 syllables instead of the 10 syllables required in English.
It is important to remember that the phonological store’s limitation is time rather than number of articles. 18 syllables are of course going to take longer to articulate than 10, so it is likely that an Italian would only remember approximately the first five digits rather than the first eight of them.