Without the apostrophe ("menus") the pronunciation would be different: the "u" would be pronounced as a 'schwa' (like the English "uuhhh...."). It wouldn't sound like the plural of the word "menu" anymore. The "u" in both "menu" and "menu's" is like the German sound "ü" and the "u" in the French "tu" (you).
If you say that for both, menu and menu's, the u is pronounced as tu (in French), then the recording isn't that good. Isn't it?
There's an apostrophe if a word ends in -a, -e (but only if it's a /ee/ and not -é!), -i, -o, -u or -y and only if this vowel is preceeded by 1 consonant.
I found this in the tips of the website I honestly think it's more clear than the reply you got
NOUN + S If the noun ends with a single vowel, you cannot just add the -s. Instead, you first add an apostrophe, and then add the -s. For instance, menu becomes menu's. There is an exception to the above rule: words ending with an -e. Those never get the apostrophe.
damn, my English punctuation is definitely gonna get mixed with Dutch, in terms of possession haha, when translating back.
''we'' and ''wij'' are basicly the same, ''we'' is more used as in: gisteren gingen we naar huis (yesterday we went home) but ''wij'' is used to put emphasis on how many persons/things were included
The last word menu's sounds to me like "men-aush", do I get it wrong or it is due to the apostrophe?
It's not correct how the man pronounces it. The way the man pronounces the word it would be written as mènuis and that is not a Dutch word. I will try to write how you should say it. Something like 'menuus', so a long 'u' and not like 'ui' as in huis (house), ui (onion). The pronounciation of the 'e' is wrong too. The way he pronounces the 'e' it sounds like the sound of a sheep (meheheheheheh) and your mouth is opening horizontal. It should be opening like pronouncing an 'o'. So more in a round form.
In Dutch, all nouns in the plural form are preceded with the 'de' article, regardless of whether the noun is a 'de' or 'het' noun in its singular form. :)
- Het huis / De huizen = The house / The houses
- De deur / De deuren = The door / The doors
- Het kasteel / De kastelen = The castle/ The castles
Thought differentiating 'de' and 'het' words is solely a matter of practice and repetition, in this case we use 'de' since it's referring to a plural noun, and plural nouns are always referred to by 'de'.
When do I ad "en" or "eren" and when do I add an "s" to make a word plural?
Another article that might help you: http://www.dutchgrammar.com/en/?n=NounsAndArticles.11