To clarify, I wasn’t actually talking about Joshua.  I was referring to the start of the book fo Judges where it says, “1After the death of Joshua, the people of Israel(A) inquired of the LORD,(B) “Who shall go up first for us against the Canaanites, to fight against them?” 2The LORD said, “Judah shall go up; behold, I have given the land into his hand."”
The question is, who is mediating between the Israelites and God at this point since Joshua is dead.  How are the Israelites hearing God’s word?  What are the possibilities?  Could it have been an angel or was it an unamed prophet telling the community since, as we know from Deuteronomy, the Israelites didn’t want to deal with God directly because they feared they might die.  That is why they dealt with Moses.

I think the possibilities would have included:

(1) an unnamed prophet
or (2) Yahweh’s response via Phinehas the High Priest using the urim/thummin
or (3) via the casting of lots (between the tribes).

In the later cases the words ascribed to Yahweh are the expression of what was determined via the employed means rather than a verbatim response spoken by a prophet.

I’d be inclined toward seeing it as a prophetic word but the text is silent and these other means could also be referred to as ‘a word from Yahweh’.