Complex sentence: She had planned on a career in the Foreign Service; fascinated by the travel and freedom her mother's only unmarried sibling, Maria, enjoyed in the diplomatic service, Russell began picking up languages in high school.
Split into simpler sentences: She had planned on a career in the Foreign Service, fascinated by the travel and freedom. Her mother's only unmarried sibling, Maria, enjoyed in the diplomatic service, so Russell began picking up languages in high school.