When I was a later childhood/ pre-adolescent (aged c.10-12), among my very favourite books were the Jennings series by Anthony Buckeridge.
These were popular among my circle, to the extent that we adopted several of the slang terms used by Jennings and his friends Darbishire, Temple, Venables etc. For example calling a rubber eraser a "bungee".
The books are set in a preparatory boarding school, which would take boys from age about seven at the youngest, up to about twelve, when they would go on to a 'public school' or a private grammar school.
I was myself state school educated, and always at co-educational schools - and I had a fairly strong dislike of boarding school stories and comic strips - such Billy Bunter. The idea of actually being sent-away to live in a boarding school - apparently populated by bullies, thieves and liars - was, for me, the stuff of nightmares, rather than of yearning day dreams.
Yet the Jennings books completely overcame these preferences and prejudices, because they were so high-spirited, were populated by benign and likeable people; and were so true to my experienced-life among boys (at its best) - and because they were so funny.
Like most of the best English humour, the funniness comes from a combination of witty usage of language, combined with embarrassing situations - especially when somebody is trying (and failing) to deal with a mishap, conceal something, or - in general - trying to stay out-of-trouble, or escape from it.
As for language, the quality of writing is very good - clearly influenced by PG Wodehouse, but with its own flavour - especially deriving from the aforementioned slang.
My own experience is that there is some degree of spontaneous linguistic creativity in any group of boys or young men; tending towards nicknames, catch phrases, and in-group terminologies. This is taken to extremes with Jennings.
The nicknames (again true to life) all have a reason, but a reason impossible for the outsider to unravel. Jennings's friend Temple is nicknamed Bod; because his initials are C.A.T., which goes to Dog, which was 'shortened' to Dogsbody; which was too-much of a mouthful for daily usage, and therefore shortened to Bod.
The school caretaker is called Old Pyjams because the school nightwatchman was nicknamed Old Nightie - which went to Old Pyjams - short for Pyjamas.
The school teacher Mr. Carter is called "Benedict" by the boys, although that is not his given-name - because of the short Latin Grace before meals: Benedicto benedicatur... Benedicatur = Benedict Carter.
The slang is often modelled on RAF (Royal Airforce) slang of the Second World War - because boys of Jennings era (and even my own) were often fascinated by aeroplanes.
The RAF had several clever and amusing slang usages - for instance a Penguin was a senior officer that had a pilot's license, but had become "chairborne", "flying a mahogany Spitfire" (i.e. a desk) - because a Penguin has wings, but does not fly*.
"Wizard" was a common term of approbation with the officers among RAF fighter pilots; and Jennings and Co. therefore use "Ozard" as an adjective of dis-approbation - from the Wizard of Oz, presumably.
There are dozens of others; many of which seem to have been invented by Buckeridge; most famously the exclamation Fossilized Fish-hooks! This goes with a tendency to call people variations on "prehistoric ruin", "ancient relic" and the like.
Similarly, the catch phrases often incorporate RAF terminology, in a loose sense, as when Jennings says
"It's the Archbeako's garden [i.e the Headmaster's - schoolmasters in general being "beaks"].
"He attacks at zero feet with all ammo blazing, if he finds anyone in here."
That is when the boys are not actually impersonating aircraft - or machine guns, space ships or racing cars - as they move through the corridors and traverse the staircases between classrooms.
For me; the funniest 'set pieces' are of the 'cross-talk' variety, when there is some difference of apprehending the nature of a situation or topic; and two people are persistently misunderstanding each other.
These often attain surreal heights, and are capable of making me laugh aloud. For example:
Background: Jennings and his sidekick Darbishire are trying to find a goldfish that they believe to have been drained from a swimming pool into a ditch in a field; but Old Wilkie, the short-tempered teacher, is seen approaching; and they try, but fail, to hide from him in a tree.
Jennings never lies, so when asked what he is doing; from up in the branches - he tries to explain that they were looking for a goldfish.
At which Wilkie 'explodes' with his characteristic expression Corwumph! and demands they immediately report to the staff room for some kind of judgment...
Darbishire said: "You are a fool Jen!"
"Well, it wasn't my fault, " his friend defended himself. "We really were looking for a fish."
"Yes, but you put it badly. Even Old Wilkie knows fish don't live in trees, unless you're speaking alley - er, alley-something."
"Alibi?"
"No, allegorically, that's it: it means saying something that sounds quite crazy, but it's all right really, because everyone knows what you mean."
"Do they? That's more than I do!"
"Well, it's like that chunk of English we had to learn for Mr. Carter, about sermons in stones and books in the running brooks."
"You're bats!" Jennings retorted. "There wouldn't be any books in the brook unless someone had put them there."
"That's exactly what I mean. There wouldn't be any fish up a tree either because they can't climb. At least," he went on, "if one did climb a tree it'd be all over the newspapers. Big headlines: Goldfish's Amazing Feat!"
"Yes it would be, if it had any, wouldn't it?"
"Wouldn't it what?"
"It'd be amazing if a goldfish had got any feet."
Darbishire began to realize that they were talking at cross-purposes. Curtly he said: "No, you ancient relic, I didn't mean that sort of feet."
"For heaven's sake stop talking nonsense," Jennings answered. "There's no point in arguing about what sort of feet it's got, if it hasn't got any."
(From Jennings' Little Hut, 1951)
*Note: Getting your wings was RAF slang for gaining the pilot's license, because this allowed you to have the coveted double-wings symbol applied to the uniform. Aircrew who were not pilots - initially observers (who were, at the start of WWI, actually of higher status, and often higher rank, than pilots) had a single wing attached to a circle with an O - or later other inital/s - in the middle. Consequently, these were sometimes nicknamed, by pilots, "the flying arseholes".
