Among themselves, the Li family Daoists chat (guada 呱嗒) in Yanggao dialect, which is quite tough to understand, in pronunciation, tones, and vocabulary. From my book:
Most north Chinese dialects are supposed to be close enough to standard Chinese, but some people from Beijing find Yanggao peasants nearly as hard to understand as I do. Li Manshan sometimes makes an effort to speak with me in something he imagines to resemble standard Chinese (as on his voiceovers for our film), but he generally forgets, which is both flattering and frustrating; and their chat among themselves is largely impenetrable. Weirdly, the only subject on which we can communicate reliably is the titles of obscure medieval ritual sequences and hymns.
Several pronunciations fox my Beijing friends, let alone me. Shi and si, and zhi and zi, are hard to distinguish. Huang sounds like hong, and guang like gong; hou sounds like khio, hao like hou, and yao like you or yu; guo and shuo become gua and shua; li and lai are both close to lei. Baishi (funeral) becomes beisi. Several pronunciations remind me of my time in Shaanbei: hei becomes he, he becomes ha, and hai becomes hei; bai and bei are sometimes closer to bie. As in Hunan, an initial N often becomes L; so “rich peasant” (funong) is fulong. The often-used term kabulei (“fantastic”) would be kebulai in standard Chinese. I like duohuir (“When?”), more classically economical than the cumbersome standard shenme shihou.
One feature of Yanggao dialect that does strike me is how the descending fourth tone is used with abandon, notably in place of the low dipping third tone, as in hashui (drinking water), pijiu (beer), fanguanr (restaurant), or ritual terms like dagu (playing drum) and xietu (Thanking the Earth)—all with a heavy accent on the final falling syllable. With my notoriously poor grasp of the tones, this becomes something of a relief to me: if in doubt, use the fourth tone!
So on behalf of “cultured” outsiders (see this joke), they sometimes make an effort to speak the Yanggao version of putonghua Standard Chinese, whose acronym is Yangpu 阳普. It doesn’t bear much more resemblance to the standard language than my own crap Chinese—which by the same process I acronymise to Lunpu 伦普, short for Lundun putonghua (London Standard Chinese). When meeting Confucius Institutes, I boldly seek to upgrade this to Lunyu 論語, “The Confucian Analects”. Hey ho.
For the secret language of blind shawm players around Yanggao, see here.