Though I personally only know of the irish origin it is possible that
Alana has more than one meaning, it could be that two or more different names that look and sound the same have originated from more than one culture,
look at
Kim for example
KIM (1)
Gender: Feminine
Usage: English
Pronounced:
KIM [key]
Short form of
KIMBERLY KIM (2)
Gender: Masculine
Usage: Scandinavian
Scandinavian short form of
JOACHIM KIM (3)
Gender: Feminine
Usage: Vietnamese
Means "golden" in Vietnamese.
Of corse a lot of baby name sites are not that bothered about how accurate the meaning is they only list meanings that are cute or pretty so you have to take them with a dose of salt