When you select a Category that contains Products and those Products come from multiple manufacturers you get the option to: Filter by manufacturers' dropdown

When you select a Manufacturer that contains Products and those Products come from multiple Categories you get the option to: Filter by Categories' dropdown

You could change the text but you would have a very odd display as the dropdown is not related to Sorting ... it is related to selecting a "few" of the Products based on the Category list or Manufacturer list or the Search list that is being displayed ...

In the Product Listing ... for Sorting, you click on the Titles to manage the Sort Order ...



When on one of the Other Listings for:
New Listing
Featured Listing
All Listing

There is a Sort by: dropdown for changing how the Products display ... instead of titles as there are no "titles" on these listings ...