This section contains information about magical animals in the Harry Potter universe.
There is a huge tendency among fan fiction authors to assume that many, or most magical animals are also sapient. The magical world necessarily creates some ambiguity here. How do you handle a world in which a sphinx asks riddles, a jarvey insults you, or in which you must not insult a hippogriff? Then we have the questions that parseltongue poses, and the canonical snakes speaking in books one, two and seven. Even if we accept the back story for Nagini from [Fantastic Beasts] and thus set aside book seven (as that snake is actually a person permanently transformed), books one and two remain as stumbling blocks.
My own take, shared by at least some other authors, is that in the case of parseltongue, the magic inherent in this language imbues in the snake abilities it does not inherently have. See the parseltongue page for details. This allows for a nuanced approach to other animals with varying levels of sentience that may or may not actually approach sapience.