Basically, because he's an animal, he can talk to animals. ... Animals don't have the brain function or the necessary vocal chords to enunciate in the human language effectively but since Chopper ate the hito hito fruit he now has both but is also able to retain his previous knowledge which humans are unaware of.

Can a Chopper talk?

Chopper in his human form. ... It also gave him human level intelligence and the ability to speak human language.

Why does Chopper have a blue nose?

Although to be fair, he was originally a reindeer. ... His blue nose caused the reindeer herd he was originally part of to isolate him. After eating the Human-Human Fruit, he was further isolated by his herd which led to Chopper leaving and attempting to live with the humans on Drum Island.