pieces

In English, count nouns refer to things that are countable, such as books and pens, while mass nouns refer to uncountable things, like coffee or sugar. In Standard English, furniture, luggage, advice, and research are all mass nouns.

The purpose of the phrase piece of is to allow us to count a mass noun, so we can say "a piece of furniture", "two pieces of luggage", etc.

However, look at the sign on the right in a Brunei supermarket. Note that piece is being used to refer to apples, even though apple is normally a count noun. In Standard English, we would say "ten apples", not *"ten pieces of apple" (unless we are referring to sliced fruit).

Two changes seem to be happening in New Varieties of English, such as that of Brunei:

• logically countable things, like furniture and luggage, are being treated as count nouns
• piece can be used together with a count noun such as apple

Both these changes are extremely common in New Varieties of English, for example in Singapore as well as Brunei. It is not clear if they will become acceptable as part of standard World English in the future, but this seems quite likely, as, in reality, treating furniture and luggage as mass nouns is not very logical when it is perfectly easy to count them. Furthermore, I think everyone can understand the sign shown above perfectly easily, even if it is not (yet) completely grammatical in Standard English.