I was wondering if the majority of the people in Al-Andalus spoke the arabic Andalusian dialect, or Mozarabic.
I'm aware that the ruling class would have spoken an arabic dialect, but what about the majority of the people? I'm sure that during the early stages of muslim occupation the majority of people would be speaking various latin derived languages, but what about the 13th century, or later?
You are correct in assuming the process of Arabization was quite slow and gradual - and basically went hand in hand with that of conversion to Islam. Most locals initially stayed Christian (or Jewish) and continued speaking a Romance vernacular. The Arabization would be more or less complete by the late 11th or early 12th century, though. Everybody who would rather stay Christian would have crossed into Christian lands by then. So when the Reconquest starts in earnest around the 1050s most of the population in the (re)conquered lands is already Muslim and speaking an Arabic language variety.
You may also want to check out this [earlier thread] (https://old.reddit.com/r/AskHistorians/comments/44za9m/during_the_islamic_rule_of_spain_did_muslims/) for more details