How do I know it is apples plural not singular in this particular sentence?
I played it many times and never got "Horses like" Is this vague enunciation deliberate?
Horse = Pfert, horses = Pfer-duh!
Also, horse like = Pferd mag, horses like = Pferdee mögen. The verbs are good at giving clues too!
Das/Ein Pferd mag, (die) Pferde mögen. You always have to use an article with singular names.
Well, with singular countable nouns.
Wasser ist nass “water is wet” is fine without an article (in both languages).
when I use an e instead of the umlaut in the capital letter word, eg aepfel, I am always marked wrong. Why?
If you're running windows 10, there is an English-international keyboard that adds umlaut shortcuts without changing the general layout of the keyboard. I found it very handy to enable, that way I don't have to memorize alt codes or use the Duo accent buttons to input the keys.
Longpressing letters brings accents up on my phone (Samsung S8). The g key gives ģ and ğ.
Installing a German keyboard and change keyboard by swiping the spacebar is my preferred option though.
Also "Horses want apples" is absolutely correct and it's not taken correct here.
"Horses want apple" (with singular apple but without an article) sounds incorrect to me.
But regardless of that, it's not a correct translation for the German, which uses the plural Äpfel, not the singular Apfel, and which uses mögen (to like), not wollen (to want).
There is no German word mogen. (If you can't spell mögen, write moegen.)
And yes, mögen is the form needed for third person plural ("they") -- and is needed here because the horses are plural.
Is there a difference in pronunciation between "Apfel" (singular) and "Äpfel" (plural)?
Yes. Short ä as in Äpfel sinds like German short e, or pretty much like English short "e" as in "get" or "step".
schmecken means to taste. I’m not sure why you would want to use that in this sentence.
Sorry, don't get mad, I just couldn't see why there was emphasis on that "P".