Prepare to be amazed by these 5 extraordinary cases!
So far, there are 5 species of animals in the world of One Piece that can converse like humans.
1. Tony Tony Chopper

The first character on this list is Tony Tony Chopper, the physician of the Straw Hat Pirates. He hails from Drum Island and is the only member of the crew born in the Grand Line. Chopper is a reindeer who consumed the Human-Human Fruit, granting him the ability to transform into a human and possess the consciousness and intelligence of a human.
Therefore, it's no surprise that Chopper can study medicine and become a doctor. His dream is to one day become a doctor capable of curing any illness and wishes to travel the world in hopes of realizing this dream.
2. Pappug

Pappug is a starfish belonging to the mermaid Keimi. Surprisingly, Pappug is a renowned designer in the world of One Piece, as the owner of the Criminal brand.
What's intriguing is that Pappug can speak like a human. In his childhood, Pappug believed he was a human. Shortly after realizing he wasn't human, Pappug was able to speak human language.
3. Onimaru

Onimaru is a koma-kitsune fox of Wano, and it once fought Zoro in human form.
Onimaru consumed the mythical Zoan Devil Fruit, model: Onyudo, enabling the user to transform into an Onyudo, a type of demon resembling a large monk.
Despite never speaking in his fox form before, Onimaru communicated with Zoro when they fought at Oihagi Bridge.
This means Onimaru is similar to Chopper. After eating the Hito Hito no Mi Devil Fruit, Onimaru gained the ability to speak like a human.
4. Manticore

The Manticore is a lion-faced creature found on the second level of Impel Down.
Slightly different from others on this list, the Manticore can only speak like a human, not communicate as one. Essentially, it mimics human conversation without understanding its meaning.
5. Sphinx

Sphinx is a distinctive creature in the One Piece world, resembling a lion but with a human face and front legs adorned with feathers akin to those of a bird.
Similar to the Manticore, Sphinx can speak like a human but cannot comprehend the meaning of words.
In Impel Down Level 2, Sphinx is a dangerous beast and the boss of other creatures on this level, including the Manticore. Interestingly, Sphinx can be found on Human Island, the birthplace of Whitebeard.