Here's a breakdown:
* Sibuyas - This is the general Tagalog word for onion.
* Tagalog - This is added to differentiate shallots from other types of onions.
* Bawang - This translates to garlic, and the combination "sibuyas bawang" emphasizes the garlic-like flavor of shallots.
You can use either term, but "sibuyas tagalog" is more commonly used.