The Athletic's Jeff Gluck defended NASCAR on NBC announcer Leigh Diffey after former ESPN reporter John Kernan criticized his accent on social media.Diffey, who has been a fixture in American motorsports broadcasting for years, joined NBC Sports in 2013. He served as NBC's lead voice for Formula 1 and IndyCar and started covering NASCAR races for NBC starting in 2015. The Australian-American commentator replaced Rick Allen and became the lead Cup Series announcer at the network last season.In his latest post on X, Gluck praised Diffey and called former ESPN NASCAR host and pit reporter John Kernan's recent remarks about Diffey's accent "extremely disappointing.""It's a privilege to have someone as incredible at their job as Leigh Diffey, a world-class sports announcer, calling NASCAR races. Extremely disappointing to see comments like this about his accent. He is one of the greats and makes the races better," Jeff Gluck wrote.Gluck responded to former NASCAR reporter John Kernan's post on X, where he admitted to being "xenophobic.""If I want to hear that accent, I'll watch Formula 1. ... Sorry, guess I’m xenophobic," Kernan wrote on X.He added that stage racing "SUCKS!" and said he was done with NASCAR after hearing Diffey call a race.Diffey often hears feedback on his accent and has received major criticism from some fans over the years as well. He once said he lost a potential NASCAR job at TNT because Turner executives preferred a broadcaster without an accent calling Cup races."I thought it was normal" - Jeff Gluck post complaints on NBC's first NASCAR Cup broadcast of 2025 seasonJeff Gluck also commented on NBC's Iowa Corn 350 broadcast with Leigh Diffey last Sunday (August 3). Gluck reviewed the race on The Teardown podcast and said the broadcast felt normal after some fans shared their complaints online."I thought it was normal broadcast. I’ll tell you what I do like is Leigh Diffey. And people who are in my mentions and replies, ‘Oh, Leigh Diffey, I can’t stand the accent.’ Good lord. He's one of the best sports announcers, period. Makes it exciting. And people complain because he has an accent? Wow," Jeff Gluck said (03:30 nonwards).Meanwhile, NBC also faced harsh criticism after airing a full-screen commercial break during a close battle between William Byron and Brad Keselowski at Iowa. Fans took to X to complain that NBC interrupted the key racing moment to show commercials. Many felt NBC's broadcast mirrored the same issues that made Fox unpopular, cutting to ads and using full-screen breaks during tight battles.NBC will air the rest of the NASCAR season with Diffey in the booth. The next Cup race is scheduled for 2 p.m. ET on USA Network at Watkins Glen International on August 10.