"Seo aon phiuthar."
Translation:This is one sister.
Aon lenites. Are you reading the tips and notes for each lesson? While you can't see them from the phone app, you can get to them by going to https://duolingo.com with your phone browser. You'll have to sign in the first time, but then you can just find your way to the lesson, and when you tap on the lesson, you can see -- and choose -- "Tips And Notes".