Complex sentence: She lived in the U.S. for 12 years, and due to her extended stay outside Japan and her immersion in English at an early age, she acknowledges that she has some trouble grasping the nuances of classical Japanese poetry despite her interest in that subject.
Split into simpler sentences: She lived in the U.S. for 12 years, and due to her extended stay outside Japan and her immersion in English at an early age, her Japanese language skills suffered to some extent. As a result of that, she acknowledges that she has some trouble grasping the nuances of classical Japanese poetry despite her interest in that subject.