I would say a lot of "student slang" sounds forced.
You said already.
These also sound forced, IMO:
To whom would you like to speak.
It is I. (When answering the phone)
May I ask...
Could you possibly...
And many more.
Typo you berk. Why do you assume the worst?
"Berk", now that could be useful to many students.
Like I keep saying, teaching for recognition is one thing, teaching for production is another.
And I disagree with your approach to separating slang as only that which need be recognised and not produced. All depends on context, the students in front of you, their needs etc, and what THEY are paying YOU to do.
Sure it could, but you seem to be saying teaching students to use slang has equal validity or importance.
And i certain contexts, some I've mentioned above, it might just be of equal validity and importance. Why do you think you have the right to decide what is or is not important for certain individuals? If you're paid to teach Standard English, do so. If not, teach that which your asked to.
If I went to Newcastle and started using Geordie words, I'd stand a fair chance of actually causing offence.
What nonsense.
You seem to be saying you would encourage to claim membership of language communities they may not actually belong to.
Read the article above. There, it shows that such people are in fact welcomed into certain language communities precisely because they make an effort to use the language and behaviour of such groups.
You spend every day pushing students to learn Standard English. Do you think that you are also not encouraging students "to claim membership of language communities they may not actually belong to"?
Do you think that Standard English is an unmarked form in the eyes of all?
Ah yes, the silent conspiracy of the EFL teaching establishment.
My God, wake up! Do you think it is silent?
Is the best argument you can give against Swan really that he's a capitalist pig?
Don't be childish. Swan is very useful for those who wish to teach Standard English and play at the edges of that form, but he is like all publishers of ESL/EFL materials. He toes the line in order to make a living and gain "respect". No problem with that attitude, but don't make his work something more than it is. Ask him to publish an ESL/EFL teaching book on slang, see what he replies.
There's no point in learning slang, so don't bother", he says "be very careful how you use it".
It's not Swan I'm arguing with, it's you. You said that you would only teach the word
pants. You said you would do that no matter the context or student needs/demands. It is you who needs to heed Swan's advice.