Complex sentence: Oyungu released her first single "Happy" in 2004 and her debut album "Hatimaye" in 2008, and her second studio album "Manzili" in 2013.
Split into simpler sentences: Oyungu released her first single "Happy" in 2004 and her debut album "Hatimaye" in 2008. She released her second studio album "Manzili" in 2013.