The spanish word sensimilla does not just apply to mj as in marijuana sensimilla (seedless pot) but also uva sensimilla (seedless fruit). It's the english speaking world that apparently made it synonymous with high grade mj.

I can't help you with Vietnamese, I was only in that country 3 times all less then 12hrs to teach a communications course at LongBinh (I worked as a civilian contractor for Federal Electric ITT) and that was fine by me. I did not really like it there. I'm sure they had a name for it tho, because like Thai they had words for everything. In english we say hot, but in Thai there are 2 words for hot, one means spicy hot the other means temperture hot.

I have saved on my computer a paper on Marijuana botany / growing by R.C. Clarke, I assume it is the same person. I was unaware he wrote anything about the history of mj cultivation, but I'm sure he could have, I'm just not familiar with it.