However, in his academic writing titled Acehnese and the Aceh-Chamic Language Family (source: Acehnese and the Aceh-Chamic Language Family) , I found two arguments by Paul Sidwell, saying that:
As far as I can tell from the evidence I have assembled there is nothing to indicate a geographical location for Acehnese in relation to the present distribution of Chamic languages. For this reason my default hypothesis is that Acehnese separated from Chamic at a time before Chamic had develop any significant internal diversity. (page 225)
[…] Sometime during this early phase of language shift, perhaps before the beginning of Common Era, the Chamic speakers who were to become the Acehnese left the mainland on a journey that would ultimately end in northern Sumatra. (page 226)
Looking at these two arguments, I will be cautious to draw a conclusion that Aceh Sultanate that was began campaigns to extend its control over Northern Sumatra in 1520, was founded from Cham people. For the Chamic speakers who were to become Acehnese left the mainland before the beginning of Common Era - imagine there was 1520 years of gap.
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