I typed "The girls are reading the newspaper." Now, in hindsight, I realise that it was not "the" but rather "a".
But here's the thing, it marked me wrong and highlighted the "The girl" part of "The girls". It literally ignored the "s" on the end and marked me wrong for nothing....
gg Duolingo, gg.
As far as 'ist' and 'isst' goes, I think it's just one of those things where once we are comfortable with the language context clues will tell us which they're using. Like, you know with words like 'red' and 'read' in English or 'horse' and 'hoarse'. When someone says, 'My throat is hoarse' you just know from being comfortable with English that there's no way they're trying to say their throat is a horse.
By the conjugation of the verb, and the structure of the sentence. Just as you do for words like "fish" and "sheep" in English. But there are still some times when it could be ambiguous.
"The sheep eats" - singular
"The sheep eat" - plural
Das Mädchen isst - singular
Die Mädchen essen - plural
And it usually only makes sense to drop the article completely for plurals:
"Sheep eat" / Mädchen essen
But if you just had "Mädchen" written alone, for example on a sign, you'd have to use the context of the situation to decide which one it probably meant.
Lesen has a stem vowel change in the du and er/sie/es forms. Ich ----> lese, no change Du ----> liest, e changes to ie er/sie/es ----> liest, e changes to ie wir -----> lesen, no change irh -----> lest, no change Sie -----> lesen, no change sie -----> lesen, no change And no, Irh lesen is incorrect, it should be irh lest. Lesen can be confusing, since it has the stem vowel change, but that's only in the du and er/sie/es forms, not in the ich, wir, irh, sie, and Sie forms. I hope this was very helpful.