We’ve all had it happen at some point. The spellcaster is investigating a scene and decides to dig into their bag of tricks. They cast “Speak with Plants/Animals/Insect/Weird Blob of Goo” and they start asking questions like they would with any other NPC.
How does a GM manage that communication? Animals might be the easiest but plant’s perceptions of their surroundings would be completely alien to us. Even stranger sources might relay even more alien experiences. The player has spent a resource, we don’t want them to feel cheated, but the source of info doesn’t just change into John Doe NPC.