In the stories the word "heut" is used. Is this a mistake?
The sentence is: Wir müssen heut Nacht die Stadt verlassen, is this just a colloquial use? If so, is it used more often before certain nouns?
Vielen Dank im Voraus.
It’s basically spoken language represented in written form. You would not normally use it in written language.
Try to pronoune “heute Nacht” at normal speed. Since the sounds of t and n are pronounced with the tongue in pretty much the same position, they tend to blend together in spoken language. Human beings are generally economical when they speak (or lazy, one could argue) and avoid too hard efforts. The t is therefore not “properly” aspirated, the “explosion” of the plosive sound t does not take place. The e is dropped completely, so that the tongue can stay in the same position. Instead, the build-up of tension in your mouth is released into the n. I’m not sure how useful my description is, but experiment with the pronunciation a bit! :)
I would not call the pronunciation “heut Nacht” instead of “heute Nacht” colloquial (as the Duden does, for instance), but the normal pronunciation of German spoken at a normal speed. The weakening of already unstressed syllables is very characteristic for German. A lot of words are “shrunk”, e.g. “gehen” becomes “gehn”, “haben” becomes “habm” (assimilation of n to b > m), “das haben wir” becomes “ds hamma” (assimilation of w to m > m) when unstressed. “Kleinen” in “die kleinen Kinder” becomes “kleinn” - one syllable -, ending in a slightly longer held n. In all these examples, weak vowels (usually a weak e, which is called schwa in linguistics) are sacrificed and vowels physically pronounced in close proximity to each other melt together.
No and No again. What you (correctly) describe is part of German dialects, mainly those spoken in the south. In "high German" (Hochdeutsch) , this is not acceptable, and if you go further north in Germany, you will see much less of these things.
Sometimes contractions like "heut" is used in poetry, but of course poetry enjoys (and needs) some liberties with the language.
Edit: Jileha is right about the dropping of weak vowels, especially the 'e'. However, I feel (hear!) a complete drop only with ending vowels. "gehen" might sound like "gehn" in everyday (sloppy) speech, but I think it is not completely dropped, just extremely shortened and without any emphasis.
But things like "ds hamma" definitely is dialect.
Well, that is true, but you wouldn't normally put that in writing. And anyhow, I don't think it is a good idea to teach/promote casual or sloppy language use here. People will pick that up soon enough, either through TV or when visiting Germany.
BTW: Berlin hardly counts as being part of northern Germany, and Berlin has its own, very special dialect.
My comment on promoting sloppy language was exclusively aimed at Bastian's post. Of course students can and should ask those questions. However, I do not think that introducing more colloquial or sloppy language uses serves a good purpose. Where do you start? What is the end? We have a quite significant (ab)use of the language following the sort of language Turks speak here. It somehow became fashionable among younger Germans. Should we teach that here, or anywhere? IMHO, definitely not. It is similar to what (sometimes) is called "ebonics" in the US.