I'm currently travelling in Laos where my favourite local dish is called "larb" or "laap" (ລາບ in Lao, ลาบ in Thai).
When I described it to my Australian friend he said it sounded like a dish that was one of his favourites called "San Choi Bow" and described it as "either a southern Chinese or Vietnamese word for the spicy mince in a lettuce leaf".
I've been hunting on Wikipedia and there appears to be no English article though I have now found a Chinese Wikipedia article and the term does show up in a couple of articles on the English Wikipedia. There is lots of information on the Internet, I noticed especially from Australia. But the information is contradictory. Two Yahoo Answers questions about its origins give different answers with no further details: China, Thailand.
There's at least seven other spellings I could find, all combinations of "san" vs. "sang", "choi" vs. "choy", and "bau" vs. "bow".
To me this looks like Chinese but I couldn't find the Chinese characters and even if the dish has a Chinese name that doesn't mean it wasn't originally from a neighbouring country.
Could it be that "larb" is a Southeast Asian version of "sang choi bow" or is "sang choi bow" a Chinese name for their version of "larb"?
Sang choi bow, from the Chinese Wikipedia:
Squid larb in Thailand:
Pork laap in Laos:
Best Answer
Probably Hong Kong.
It is written in Chinese as "生菜包", which in Pinyin is "shēngcài bāo", noticeably different to any of its usual spellings in English.
However, in Cantonese it is "sang1 choi3 baau1". Much closer to the English spellings and pronunciation. Cantonese is mainly spoken in Hong Kong, a great culinary exporter and major influence on "Chinese food" in the west.
生菜
means "lettuce" and包
means "wrap", etc.It does in fact have a Wikipedia article, but only on the Chinese Wikipedia. The article is very short and Google Translate does not handle it well. I will include the Chinese text here in case any readers who can read Chinese can find something of the dish's origin or history:
Of course it's still possible the dish originated outside Hong Kong, the name is very literal and isn't necessarily the original name of the dish. But it is clear it came to the English speaking world by way of Hong Kong.