Hello Lizzy,
The neutral word order in Arabic is (Verb + Subject + Object), which, in your example, translates to (Fatima helps her mother with the housework).
However, word order is very flexible in Arabic, and without the proper vocalization, it could mean either of the suggested translations, since, in Arabic, the function of the word in a given sentence is determined by the marking it takes rather than by its position.
Let's examine the example you provided:
- تساعد فاطمةُ أمَّها في تنظيف البيت = [ tusaeid fatimt*u* omm*a*ha fi tandheef albayt ] = Fatima helps her mother with the housework.
In this case, the subject (Fatima) and the object (Her mother) both the corresponding markings (short vowels u, a respectively)
- تساعد فاطمةَ أمُّها في تنظيف البيت = [ tusaeid fatimt*a* omm*u*ha fi tandheef albayt ] = Fatima's mother helps her with the housework.
Notice that while keeping the same word order, and by exchanging the markings of the subject and object, the meaning has completely changed.
But, usually when the text in unvocalized, you can assume the neural word order that I mentioned above ( Verb + Subject + Object ).
I hope you don't have a headache after reading my answer )