I get why people focus on Devon's way of speaking — it’s one of those small, vivid choices that tells you a lot about him without needing exposition. In the world of 'Big Mouth', accents and speech patterns are shorthand for backstory, community, and attitude, and Devon’s voice does that work. To me it reads as a blend of cultural roots and teenage bravado: a rhythm and intonation that suggests he grew up in a tight-knit urban setting where humor, confidence, and a little bit of posturing are part of daily life.
On a production level, voice actors and directors often lean into a vocal flavor because it makes characters instantly recognizable in a crowded ensemble. That flavor can come from the actor’s own influences, from deliberate coaching, or from the writers wanting to signal something about Devon — maybe his family background, his peer group, or his swagger. Sometimes the show exaggerates features for
comedic effect, and sometimes it’s trying to capture something authentic. Either way, it’s meant to be entertaining and to give Devon a distinct personality. I find that those choices make the show pop: even if the accent is caricatured a touch, it helps the character stick in your head — and that’s part of why I laugh every time he talks.