Romance Languages:
* Spanish: hermanas
* Italian: sorelle
* French: sœurs
* Portuguese: irmãs
* Romanian: surori
Germanic Languages:
* German: Schwestern
* Dutch: zussen
* Swedish: systrar
* Norwegian: søstre
* Danish: søstre
* English: sisters (of course!)
Slavic Languages:
* Russian: сестры (sestři)
* Polish: siostry
* Czech: sestry
* Ukrainian: сестри (sestry)
* Bulgarian: сестри (sestry)
Other Languages:
* Arabic: أخوات (akhawāt)
* Chinese: 姐妹 (jiěmèi)
* Japanese: 姉妹 (shimai)
* Korean: 자매 (jamae)
* Hindi: बहनें (bahanen)
* Greek: αδερφές (aderfés)
* Turkish: kız kardeşler (kız kardeşler)
* Vietnamese: chị em gái (chị em gái)
This is just a small selection of languages. There are many others with unique ways to say "sisters"!