It's a bit of a misleading headline. Having read the article it is just saying that the kids can speak how they want to but are required to use more formal language in written tasks. Seems like a perfectly reasonable teaching of the concept of register to me. Now if they had said "if we hear you use slang we will punish you with extra homework" then they would be wrong but as I read it, that is not what they have done at all.
"No man but a blockhead ever wrote except for money." Samuel Johnson.
I have to record my lectures for a virtual class I am giving - and then review them. Little did I know how much I use "You know,..." Good heavens (which is probably banned too!). We have someone who does the transcripts for all our recordings and I mentioned that - he said, "Oh yes you do!" Geez (probably banned too).
Some of those slang words either I haven't heard of, or they are not used in the U.S. Have any Americans heard, "Oh my days"?
Haven't heard it, but "Oh my daze" is my usual condition. Most of us use seemingly useless words which allow our thoughts to catch up with our speech. Really fluid speech seems rare to me.
To be honest I have never heard most of the slang terms in the article but that's not the relevant point. Slang or cant is specifically intended to exclude the outsider - that's its main purpose - and when talking about a group of teenagers I'd suggest that all of us here are very much outsiders. The slang of our youth was frowned upon by our elders and their elders frowned upon the slang of their youth. It's always been that way and always will be. My point was that what the school is teaching is the concept of register and that seems to me to be a perfectly reasonable thing to do - whether I understand the slang terms or not!
"No man but a blockhead ever wrote except for money." Samuel Johnson.