not like i'm one to talk anyway, i have conversations with my cats all the time. Both ones where i speak human at them like they can understand me, and ones where i mimic the mews they make
Cat is a language of body-poses, tail-posture, scenting and subvocalization, most of which happens outside human sensory range. Cats are observed to communicate with each other in very different ways to the way they attempt communication with humans.
Domestic cats are cool because they are, in absence of human intervention, a social species. So they do have more complicated modes of communication between one another in ways that, for example, mountain lions do not.
if you believe a cat is attempting to communicate with you, it probably is; you are part of its colony, and it would reasonably expect you to fulfill certain roles. For example, one reason why cats are so chill about humans handling their babies is thought to be because unkept/feral cat colonies tend to raise babies communally.
So he can "talk" with Merrill.