DeLonge is an extreme example but far from the only singer in the genre to adopt a very particular accent, usually described as sneering, whining, bratty, or snotty. By the early-2000s, with pop-punk nearing the apex of its popularity, singers from all over California had influenced singers from as far afield as Minnesota, Ontario, Maryland, and South Florida, all of whom sung pretty much just like DeLonge, who grew up just outside San Diego.
What is going on? How did that linguistic pattern take hold? From its start, punk has played with accents, with Americans sounding like Brits and vice versa but this voice is different. It turns out that when you make a linguist listen to a Blink-182 song, you can learn alot about how regional dialects spread globally, particularly the influential cadences coming out of California. The three-minute pop punk song is not so dumb, after all.
My co-favorite “American guy[s] faking an English accent faking an American accent” of the time were Ari Katz from Lifetime:
and Chris Conley from Saves The Day: