A: Absolutely. You can install English, Spanish, and Japanese simultaneously. Each gets its own Start Menu shortcut.
Imagine an engineering firm in Germany receiving drawing files from a partner in Italy. The German engineer opens the file, but all the dimension styles, layer names, and block attributes are in Italian. By switching their UI to German, they can navigate the commands while keeping the data intact. Double-byte languages (like Japanese or Chinese) are especially tricky without a proper pack.