This chapter pictures Jerusalem as having a funeral with its typical songs. This is an image used to describe their destruction. It is a time of great sadness. The ULB sets poetry (9:1-12, 17-24) farther to the right than the rest of the text to show that it is poetry. The prophecy revealed to Jeremiah is recorded in 8:5-9:12. Despite covering more than one chapter, this should be seen as one unit.
"my people, who are like Yahweh's daughter". Yahweh shows his love for his people by speaking of them as a daughter. Here Jeremiah uses this same phrase for the people. See Jeremiah 4:11.