Leicester

When I went to London, last month, I noticed that many words are pronounced in a pretty weird way like “Leicester” and “Gloucester”… in both words you don’t hear the “ce”.  Why does it happen? Vincenzo

Unfortunately, that’s just the way it is! Italian is a phonetic language, while English isn’t. This is why Italians have problems with English pronunciation, and why English mother-tongue speakers have problems with Italian pronunciation.
But you’ve probably noticed that with many English words (and not just place names) the spelling is different from the pronunciation. Take “right” and “wrong” for example.