It has not escaped me how Dex mirrors the people he fixates on, and it's often revealed in his tone of voice or choice of words.
In s3 DD, he mirrored Julie for a little bit, but when he was working for Fisk, I noticed he took on Fisk's cadence. It's subtle, but it's there, in the way he says "we are not done".
In s2 DDBA, when he was on his "time to help matt (by killing fisk)!" bullshit, I noticed sometimes he leaned into Matt's tone of voice, to the point where their voices were blending in my head.
The few times he spoke in ways that didn't feel influenced by others, was when he was talking to Karen in that beautiful shirtless gun scene.
And not to promote my Dex fic, but he also regurgitate what other people say to appear more human, which is why in my fic I emphasized his desire for honesty, which derives not from his own self but from Dr. Mercer telling him from a young age "Be honest, we like honesty around here."
He learned honesty from Mercer but he never actually applied much honesty to his life because he was too busy pretending to be normal.
But what does honesty truly look like to Dex? Honesty is rarely words. It's an exchange of silence, it's violence, and it's admitting he likes violence.
I'm certain he feels like an animal, and that he's uncomfortable with it to some degree, which is why he asked Matt in DDBA S1 E8:
The most genuine he felt was actually when he wasn't speaking. That scene of him killing his copycat, with the wordless grunts and low chuckles. That right there is Dex.
Practicing honesty, to Dex, is becoming Bullseye