The Dutch was among the earliest European to enter the Southeast Asia in their way to search and conquer the spice trade route. The Dutch manage to extend their control in Malacca after defeated the Portuguese in 1641. Since then, the Dutch introduced their own currency system via the trading company, Venerisch Oest-Indische Companie - V.O.C. from 1602 to 1799.
The silver coins that they introduced to the Malaya peninsular were known as "Daalder" which sounds closely to "Dollar" according to the Dutch pronunciation. Meanwhile, they also used the fractional silver coins known as "Stuiver" or "Stiver". The most popular fractional silver coin was the "2-Stiver-piece". The Dutch recognised it s "Double-tje" and the Malays as a whole used to named the silver coin as "One Wang".
The word "Wang" was indeed transformed from the currency units of that introduced by the Dutch and was adopted commonly by the local. However, the word "Wang" today has expanded its meaning further and it is used to represent general money in our daily life. "Ada Wang tak?" or "Do you have any money?" and that's how we interpret it nowadays.