Ayo Edebiri taking over the Missy Foreman-Greenwald role from Jenny Slate after Slate stepped down so Missy can be played by a Black actress fits right in on a show that emphasizes how growing up means learning from your mistakes. "Edebiri maintains the girlish quality that was so central to Slate’s vocal performance but brings the pitch down just a tad so that Missy sounds closer to the adult she is in the process of becoming," says Jen Chaney of the transition late in Season 4. "It is a change handled with sensitivity and real grace. This season of Big Mouth leans hard on the notion that this moment for the characters, who are now in eighth grade, marks a time when kids look harder at themselves in mirrors — both the fun house and regular kind — and question more deeply whether whom they see is the person they want to be. Appropriately, the series itself seems to be going through that process and holding itself to higher standards. That applies to the course correction with regard to Missy’s race and to its introduction of a trans character named Natalie, voiced by Josie Totah of the new Saved by the Bell. After being criticized for its handling of a pansexual story line in season three, the show does a much better job of portraying Natalie, who comes to summer camp after transitioning and feels disconnected from the boys she used to be friends with as well as many of the snobby girls. Natalie is not insecure nor truly hurt by the way she’s treated — she’s a kid who knows exactly who she is but happens to be stuck in an environment where everyone else is not quite as enlightened, which is refreshing to watch, especially once she and Jessi become allies. If all this talk of serious 'issues' makes Big Mouth season four sound like one long very special episode, rest assured that this series is still as funny and profane as it’s ever been. Entire sections of episodes focus on constipation, the agony of a heavy-flow period, and the many steps involved in ensuring that one can masturbate in peace and privacy."
Ayo Edebiri credits Big Mouth having Black writers for paving the way for the Missy recasting: "We’re figuring it out," she says of the show approaching issues about race. "But I think that part of doing that means having conversations. Sometimes, maybe, they’ll be funny. Sometimes they’ll be serious. Sometimes, they’ll be nice. And sometimes they’ll be uncomfortable and not completely concrete, or you might not be getting the answer that you want or need. But I think having those conversations is a big part of it. I think another big part is having people in the room and actually listening to them. Not just hiring people because they check off a box. Like, hiring them because you value their voice and what they have to say. I think part of the recasting, not just came from Jenny but also from having Black writers and other writers of color in the room who said, 'This needs to happen.' Making sure that you’re actually listening to those voices and uplifting them and promoting them and not just having them on camera or in front of the camera or the vocal talent or whatever but having them in positions of influence."
Edebiri found Missy's voice through trial and error: "What Jenny did was so specific and fun, and I really worked with the producers in finding that, and I think that meant trying a bunch of different things," she says. "It isn’t just like it was in my head sitting quietly and then I hopped in the booth and was like, 'I got it,' and everyone was like, 'Great job!' It is a lot of trial and error, which I think is what makes voiceover work so fun, because it is a lot more hands-on. It is very involved and interactive and I got to try a bunch of different things, and it was a combo of what feels right to me and what the producers felt good about."
Big Mouth is less raunchy and more introspective in Season 4: "Most people regurgitate the same advice about middle school: growing up is hard," says Kayla Cobb. "For the past three seasons Big Mouth has chronicled in deeply disturbing detail all the ways that statement is physically true, from masturbation-obsessed preteens and boys mourning lost pubes, to flirting with your cousin and fretting over periods. But Season 4 is the first time the series has committed to chronicling the internal truth behind that age-old advice. Growing up is hard; not just physically, but also emotionally and mentally. Whenever Big Mouth has embodied mental health struggles it’s been at its best. David Thewlis haunted Season 2 as the Shame Wizard, a being who takes any unsavory action and magnifies it to be as internally devastating as possible. Jean Smart did the same in Season 3 with her Depression Kitty, a giant cat who convinced the smart and driven Jessi (Jessi Klein) that it was easier to give up than try. These moments were as insightful and painfully funny as Big Mouth so often is, brilliantly balancing the unspoken truth of how powerful these emotions are with their silly cartoon counterparts. But as excellent as they were, they were often few and far between. On that front, Season 4 completely flips the script. The masturbation, period, and Hormone Monster jokes are still there, and they’re still raunchy, but for once it’s the mental health of these budding adults that takes center stage. What’s especially impressive is that each kid’s internal struggle is drastically different than the next."
Jessi Klein's willingness to poke and prod at her own most vulnerable moments has made her a natural fit on Big Mouth: “Jessi has instinctively, throughout her career, scrutinized her horniness and her awkwardness,” says Kroll. “Now that might feel a little commonplace — a comic nostalgically looking back at their own awkward youthfulness or horniness — but Jessi was an early adopter.” Klein adds: "I’m at a place in my life right now where I’m dealing with more hormones again. And in some ways, it’s like a second adolescence. It’s like that girl telling me that I didn’t look good in her striped shirt. We’re laughing now, but it was truly decimating to me at the time. Having the opportunity to get into the booth and scream like my 12-year-old self is an appropriate outlet for how my 45-year-old self is also feeling. So, yeah, reliving those moments is pretty cathartic."