She is studying Russian and Polish, both belonging to the Slavonic language family.

Slavonic 是形容词，来自名词 Slav（斯拉夫人），加上后缀 -onic 构成，表示"与斯拉夫人或斯拉夫文化相关的"。Slavonic language family 指"斯拉夫语族"，包括俄语、波兰语、捷克语等源自斯拉夫民族的语言。