Is "She eats an apple." and "She is eating an apple." the same in Irish? Or are there two different verb forms?
There are two different verb forms. Itheann sí úll is "she eats an apple", whereas Tá sí ag ithe úill is "She is eating an apple"
Why is "apple" in genitive in the latter phrase?
Because the object of a verbal noun is in the genitive.
When do I use "sí" instead of í? Could someone help me please?
Sí is used instead of í if it’s the subject of a sentence and if it directly follows the sentence’s verb.
Why is there no "a" or "an" in this language?
Not all languages have all articles; for example, English doesn’t have indefinite plural articles, French has partitive articles, Arabic (like Irish) has only definite articles, and Russian has no articles.
Then why my answer "she eats apple" was not accepted?
Because unlike Irish, English does have an indefinite singular article.
How do you know it's she and not he?
Sí means “she”, and sé means “he”.
Is "I eat an apple" "Ithim úll" or am I missing something?
Yes, “I eat an apple” is Ithim úll.
Why is it Is cailin si but not itheann ull si?
It’s Is cailín í, not Is cailín sí.
Itheann úll í would mean “An apple eats her/it”. Irish, like English, can depend upon word order to distinguish subject from object.
When do i know whether it's "she eats an apple" or "she eats the apple"
“An apple” is úll, and “the apple” is an t-úll.
How do I know when to use Itheann or Ithim?
What order is the Subject Verb and Object in this language?
Took half an hour to finnaly get to the page, but thanks none the less.
So there is no indefinite article in Irish? "an" means only "the" right?
Yes, that's right. "An" changes to "na" in the plural form, but it still means the same as the English "the".
do you need the "si"????
Yes, you need the sí.
Itheann úll means "an apple eats".