"Viserys aōhor hāedri jorrāelza."

Translation: Viserys loves your younger sister.

[Tiff382466]

The use of younger sister seems arbitrary since the exact same word is used for sister

[Dedalvs]

This is because there is no word that is the equivalent of the English word "sister". The word "sister" in English corresponds to two High Valyrian words, neither exactly. The word hāedar can be translated as "sister" (technically true) or "younger sister". In English, though, if you write "younger sister", the appropriate translation is only hāedar.