Story-writing bloopers

I don't know if anyone has ever read the Harold Shea stories by L. Sprague de Camp and Fletcher Pratt, but they were originally written in the '40's and '50's. In them there is an attempt to replicate the slang of the time and it comes across as highly anachronistic and not all that easy to decipher for a modern reader. If you plonked someone from the '40's or '50's into a modern setting and expected them to understand modern idioms with all the pop culture references and none of the background to go with it I have no doubt that they would also struggle. What do you mean 'mobile phone'? How do you surf on a net? What on earth is a 'booty'?

And that is why rip van winkle is amusing for us despite the horror of his situation

I think it's worth reproducing things like slightly different word order or a tendency to miss out "the" and "a". For the most part they don't confuse the reader and they do give authenticity - if correct. I tried hard with my 1640s England story "The World Turned Upside Down" to make the dialogue genuine and no-one said they struggled with it. For example, at that time people said "I saw it not" rather than "I didn't see it", but we understand "I saw it not" perfectly. Go further back and of course it gets harder. As for distinctive words and slang, I'd say include them if the meaning is clear but don't pack the story with words or phrases that need a footnote. This sort of thing is much easier with the internet as you can find all sorts of contemporary texts with dialogue.

As for Seegee's comment, this recalls the British series "Life on Mars" (I think it was remade for the US) in which a police detective appears to wake up some twenty years in the past but in the same job. "Where's my mobile?" "Your mobile what, sir?"

Ah yes Life on Mars, both that and it's follow up Ashes to Ashes were great shows and they do illustrate my point.