When he calls in response to an email, Cal Arnold tells me he's on his way home from school. The 17-year-old is nothing if not a multitasker: as well as studying and updating his YouTube channel, he's a budding actor, most recently appearing in The Windermere Children, a BBC film. "I like being busy," he says.
Arnold, from Dublin, started making YouTube videos at the age of eight, mainly working with flat motion graphics. As he puts it: "I would get Lego figures and take lots of pictures and make them move, basically."
His channel began to take off in 2017 after he posted an eight-minute video on the differences between Irish and English slang, which is now at over 1.2 million views. It featured a British friend trying to guess the meaning of different Irish colloquialisms, prompting much confusion over terms like "mot".
"A lot of my friends are on YouTube as well so we can make videos with each other," he says. "We're never stuck for ideas, and we share the same audiences."
His followers are in the main teenagers, both male and female.
Although he's worked with two major international brands, Arnold's views are generally not high enough yet to bring in much money from advertising revenue. For him, however, YouTube has always been a passion project, even if he does occasionally get some flak for his content.
"There's always going to be negative feedback but it doesn't bother me," he says. "It's something you have to expect if you start a YouTube channel here, especially as a teenager; the lads are going to slag you. It goes over my head, though, probably because I started so young. I've also made a lot of friends through YouTube, and those are people who completely understand where I'm coming from."