In Mandarin “o” is pronounced “all”. “Bohai” is pronounced as “ball-hi”
The video pronounced it right. 渤(海) is spelled as B
o, but in practice it is pronounced as B
uo. There is a slight
u sound ahead of
o. English word
all does not have that u. The closest English sound is f
our.
There is a big controversial of whether O or UO is right in spelling certain words. It even reached the ministry of education who insisted on O being the standard spelling. Interestingly most people assumed UO in place of O (the standard spelling) including myself. I only realized this "mistake" when looking up in dictionary.
The following link quotated a member of the standardization as saying that
o is a shortened version of
uo in spelling, meaning it is written as
o but pronounced as
uo, example is bo po mo fo are actually pronounced as buo puo muo fuo.
This link stated 99.8% error rate of
o. It is like saying nearly all Chinese are wrong since the creation of standard mandarian except the very few "experts". How ironic is that!
有学者调查发现,“o”的误读率达到了99.8%
I personally must say that both the linguistics and the ministry are trying to defend their bad choice of spelling scheme (1950s) in their work (the standardization) ignoring the actual practice of the population.