Champa language is a close relative to proto-malay and old-malay languages. Originally 'garam' (meaning salt) was not in their original language vocabulary but it's believed to be introduced by the sea traders from the word garum for the salty fermented fish sauce that was once very popular in Roman, now a very common food sauces in South East Asia including Thailand and Vietnam [2]. Based on ancient Roman record for example Geoponika, the garum was normally used as salt replacement in their diets and probably due to its popularity perhaps it is considered as salt by the native Champa people and most probably where the word garam got its name about 2000 years ago.
[1] The Cham: Descendants of Ancient Rulers of South China Sea Watch Maritime Dispute From Sidelines:
https://www.nationalgeographic.com/science/article/140616-so...
[2] Garum:
I'm not sure we can confidently assert that it was a salt replacement in all cases, because anyone living on the ocean has an infinite supply of salt which is impossible not to discover, nor can one claim it was not an original development in the region, because fermenting fish is self-advertising. However, I think the extent to which Romans used garum as a trade good combined with other Roman findings is sufficient attestation that a Roman version may have arrived at least once as a further link within trade networks via Indian shores. Local historiography is extremely sketchy in this period, relying on isolated Chinese references.
Whatever happened, local culinary traditions would have already been well established by (1) local geography; (2) Austronesian peoples; (3) prior links from shorter distance coastal trading; and (4) Indian states' long distance voyaging. To assert they had no supply of salt or had never discovered fermented fish would be difficult at best.
The Makasar traded with Aboriginal people for trepang (sea cucumber), which they boiled down, dried on their boats and traded with China where it was, and still is used for food and medicine.
That trade was ongoing when the Dutch first arrived in East Indies, they burnt a lot of local records of the existing kingdoms so it's hard to know how far back such trade went on for - although this suggests regional trade going back to at least 4 BC.
https://en.wikipedia.org/wiki/Makassan_contact_with_Australi...
My comment back story is I was joining up the far end of the Silk Road
> the silk road was almost 500 years old by then. Money flows.
with the Trepang trade, which would have gone past Bali on the way.
Superfluous in any case, the spice trade alone would be sufficient to extend Silk Road trade beyond China and into what would later be called the Dutch East Indies.