I always hear something like "men'uis"... Is it bad audio, bad ears, or is it supposed to sound like that? I thought the "u" sound would stay the same only that there is an additional "s" at the end?
That's right. I heard it too. The pronunciation is officially just: /meenuus/ Not /meenuis/.
Yes, because it's easier to read and pronounce. All nouns ending with the long vowel sounds (except e) in singular and -s in plural get an apostrophe.
When to use an apostrophe is a standard rule in Dutch spelling (I don't think there are any exceptions). See explanation at the end of the opening post here. It is totally unrelated to how it is used in English, but in some situations it can appear that they are used in the same way, so that can be confusing:
- the twee Peters eten = the two Peters eat
- Peters boek = Peter's book
- Mary's boek = Mary's book
- Bas' boek = Bas' book
- de menu's = the menus
No, the word order is unnatural (consider saying in English: I write menus not), and you would use geen here.
So why does "Ik schrijf menu's niet" not work? Doesn't it describe the verb "schrijf"?
The sentence is that you don't write menus, not that you don't write. Hence, the negation refers to menus as while you don't write menus you may still write books/letters/poems etc.