"عِنْد روزا سَمَك."
Translation:Rosa has fish.
I hear it too, it's Ruuz-an. The final ا sometimes has a little mark on top that looks like a doubled form of the stroke for short 'a', and is pronounced 'an'. But, it requires certain grammatical contexts (technically it's accusative indefinite). It wouldn't be correct here. But, I think it's simply the TTS over-predicting when it should be pronounced.
You have to read the Tips and notes section, it is explained there. You find it under the light bulb symbol for each lesson, in this case the lesson would be "Omar is..." . It's only available on the website though, not in the app.