There are no actual genetic differences between dawb and lees. In the past, Hmoob dawb lived around other Hmoob dawb (ditto with Hmoob lees) and developed common word usage. That's it. For example, Hmoob lees calls a blanket "choj". In Hmoob dawb, "choj" is bridge. It's not a true dialect difference! We all still know the word "choj" but we just use it in difference context because my great-great-great grandfather used it the same as his neighbor because his neighbor's great-grandparents, whom also lived and died in the surrounding area, also used it as such. The same can be said about little nuances in the ancestor worship, rituals, and culture.
It's like if a person never leaves the east coast of USA and he visits Minnesota for the first time and we call Pepsi/Coke "pop" and he's like "What the hell is 'pop'"? Does that mean he speaks a different dialect? No. He knows what the word "pop" is but Midwesterners simply all started calling it "pop" so it became "pop".
You guys are out of touch with reality if you think that Hmoob dawb are more vocal than Hmoob lees or anything like that. Our cultures and genetics are 99.99999999999 999...% similar. The same goes for the Sapa Hmoob dub in Vietnam. Don't give me that bullshit about how the dress and do rituals slightly different so they are somehow a different Hmong. When you can comprehend 99% of each other's language, you developed regional differences in word usages. You do not represent different dialects.