"an Arab woman and an American woman"
Translation:اِمْرَأة عَرَبِيّة وَامْرَأة أَمْريكِيّة
It's because of the وَ in front of the word. The ا in امرأة doesn't have any sound on it's own. It takes the sound of the word before it.
The ا letter in the word امرأة is called "Hamazt Alwasl" and it shouldn't be written without a kasra under it.