It may be difficult to understand quickly-spoken Japanese if you haven’t practiced doing so. However, there just so happens to be a show in which the characters talk especially quickly. That show is オー！マイキー. As a plus, they mostly talk about things which don’t require much vocabulary to understand. It might be good for listening comprehension. It’s also just a funny show.
Example of some scenes from it: (of the twins, the ones who talk the fastest.)
Haha, I knew this show as The Fuccons! Never realised it was a Japanese show.
It was shown on HiDive dubbed in English whenever they had technical difficulties. Such a silly show.
That gave me some chuckles. ^^ 「僕たちマイキーを待ってるなんて言ってないよぉぉぉ～」
I do think my wife wanted to snap my laptop in half after a few minutes, so I switched to headphones. 
What an unfortunate name And what’s with all the scrolling text? I see that sometimes and it’s just obnoxious ^^
That said, I don’t think they are speaking particularly fast.
Could be an anti-contend id move (i.e. adding noise to the frames so that the algorithm doesn’t match it to the copyright owner’s content)?
Probably doesn’t help though…
I’ll have to agree. Not as fast as in some talk shows where people could even be talking over each other.
Yeah, agreed. Fast scripted speaking is still much clearer, and often slower than fast native speaking.
Those are from the Japanese video site Niconico! Their signature feature is allowing users to type comments at specific timestamps in the video, causing them to scroll by like that as you watch. Sometimes people get creative with it, which can be pretty funny.
Looks like in this case, somebody reuploaded a video from there to YouTube, keeping those comments intact.
Thanks for sharing this! For some reason the alien calling part really got me
The Disastrous Life of Saiki K. has plenty fast dialogue and (inner) monologue.
If we’re going for recommendations: I’m watching a Pokémon Shield LP by だいだら. He tends to speak pretty fast, and especially speeds along as he’s reading text in the game.
Yes, that’s a NicoNico video for sure. You can turn them off while watching, but it’s sort of part of the whole experience I guess! 