This is a question all of us Ongs have heard many, many times. And as I've written before, the Ongs are English, with known traces of "Onge" found as early as the 13th century. So we're as English as the Queen, if not more so!
But what does Ong (or Onge) mean?
There are many theories for the origin of the name. Many are wild and speculative, but the only scholarly etymological source I have seen is by Henry Barber in his "British Family Names" (London 1903). It has the following entry (my explanations of the abbreviations are indicated by "(=xx)"):
ONG. N (=Old Norse/Icelandic) Ungi (?) (the younger); F (=Frisian)
Onke, dimin. of Onno; G (=German) Unger; Fl (=Flemish) Ongers; p.n.
(=place name) or Ongar; a loc. n; Essex.
It's somewhat speculative, but I prefer the idea that Ong is a Nordic cognate of young or younger. In fact the modern Danish word for young is "unge" and modern Norwegian for young is "ung". And given early medieval English history, Nordic or "Viking" sources are pretty likely for an East Anglian family.
Michael Linwood in his history of Barningham, Suffolk, "Our Own People" highlights the early (and long-lasting) association of the Ong family with the village and offers the following observation:
"Inherited names were not customary amongst the ordinary people in Anglo-Saxon times, but the name Ong seems to have Old Norse origins. It gives rise to the theory that Viking families had been clinging to their Danish origins since they invaded and remained conscious of their individual cultural background."
The Viking influence in eastern and northern England dates from 865 when the "Danes" landed a large army in East Anglia (which includes Suffolk). By 867 the Danes had conquered the Kingdom or Northumbria with its capital in York and in 869 conquered the Kingdom of East Anglia, defeating King Edmund the Martyr, subsequently enshrined in St Edmundsbury Abbey (in today's Bury St Edmunds, the principal town of West Suffolk).
After conquering most of the central Anglo-Saxon Kingdom of Mercia, the Danes were defeated by King Alfred (the "Great") of Wessex in 878, but the subsequent treaty with the Danish leader Guthrum in 880 granted the new Norse settlers self-rule over most of North and Eastern England, known as the "Danelaw". Norse settlers continued to emigrate to England in this period, although they were quasi-assimilated into Anglo-Saxon society and substantially converted to Christianity. Viking attempts to re-establish states in England continued until 1075, by which time England had been conquered by the Normans (1066) of Northern France (themselves originally of Norse origin as suggested by their name).
So to be English a thousand years ago could certainly mean living in what we would today call a multi-ethnic culture. I recently did a DNA test which revealed that my ancestry was 14% "Scandinavian", even though according to family lore and my (wide, but not complete) knowledge of ancestral surnames I have no known Scandinavian ancestors. Maybe that is where the Ong DNA resides!
Some of my cousins have changed their names from Ong to St.Onge (a corruption of the French province of Saintonge) or DeOng on the assumption that our name was originally French, and a restoration to something more Gallic-sounding would be more accurate (and perhaps less Asian-sounding). Well there are quite a number of French-Canadian St.Onges out there, but they're no relation to us. So sorry guys, you're wrong: Say it loud, I'm "Ong" and I'm proud!