This Quirk allows Koji to vocally communicate and command animals to follow his will.
The animals in question just require to be within Koji's vocal range in order to be influenced by his Quirk. It's still unknown if animals affected by Anivoice follow Koji's orders willingly or if they are forced to.
This Quirk is sound-based and, because of that, any louder noises can disrupt its effects, either by drowning out Koji's voice or scaring away nearby animals. Koji also cannot control artificial creatures that have been shaped to resemble real animals. Additionally, Koji's fear of bugs restricts the effectiveness of the Quirk when used on insects.