The call number area for Italian dictionaries and other language books begins at PC1640. There are many non-circulating dictionaries in the Reference Collection on the 2nd floor of Alden Library. For volumes which you can check out, try the same call number area on the 7th floor.
We have dozens of Italian dictionaries. Here are links to listings in ALICE:
We have many books on Italian grammar and usage, mostly in the PC1111-PC1112 call number range. Here are a couple of sample titles:
Here's a link to search results in ALICE for many additional books on Italian grammar, mostly in the PC1111-PC 1112 call number area on the 7th floor.