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
Short form of KIMBERLY KIM
Scandinavian short form of JOACHIM KIM
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