"In Laos, we bring 7-8 companies to the table compared with 30-40 companies that Vietnam brings. But China—that's a totally different ball game," said Anthony Nelson, director of the U.S.-ASEAN business council.

"So there's no coincidence that the countries with the lowest levels of development, Laos and Cambodia, are the most willing to advocate for China's position in international discussions."

But the Lao are closer culturally to Vietnam than they are to China. Their businesses use Lao language signs and mixed Lao-Vietnamese families incorporate local customs, while Lao-Chinese families tend to be isolated.

"We are a bit frustrated with (China). They create their own ecosystem," a Lao businessman said.