Ostension, the Builder
The question addressed in this Remark is: what distinguishes different uses of a single word-string? In comparing the use of the phrase "five slabs" in Remark 8 with its use in this one, Lois Shawver suggests:
the important thing [is] that "Five slabs!" in (8) causes the worker to bring 5 slabs [w]hile "five slabs" in (21) only causes the supervisor to have information.
And from one perspective, that seems right. But one who views organisms - including humans - from the perspective of stimulus-response (as I do) will want to describe the distinction in terms of a hearer's action in response to a speaker's utterance rather in terms of a change in the hearer's epistemic state.
And this highlights a recurring theme of the early Remarks: the importance of context in determining meaning, interpreted here as being the responsive action a speaker's words are intended to motivate a hearer to take. In Remark 8, it is assumed that due to prior instruction (discussed in Remark 6) both A and B understand that A's intent in issuing the command "five slabs" is for B to bring five slabs to a location indicated by A. And in this Remark, it is similarly assumed that B's report "five slabs" is the kind of response A intended to evoke in B by issuing a query. But without further contextual information, we have no way of knowing what A's response to B's report "five slabs" might be. Or put in W's terms, we don't know the rest of the rules of this "language game".