Vercast carries 20 languages, including right-to-left scripts. Three separate ideas are worth keeping apart.
Libraries
A library is the set of songs in one language, downloaded to your device. Choose them under Settings → Libraries and languages. Up to five at a time.
Translations
A translation is the same song in a different language, kept as its own linked song. Where one exists you can move to it from the reader.
Transliterations
A transliteration is the same words in a different script — the sounds of the original, written so you can read them. If you sing in a language you don't read, this is the one you want. You can hold up to five transliteration and five translation preferences.
Search understands transliterations. Typing a romanized title finds the song even though it's stored in its native script.
Right-to-left
Hebrew, Arabic and Urdu render right-to-left. The controls stay where your thumb expects them.