Regional pronunciations of standard Mandarin
I can't think of any tables I've seen, but I can share some of the patterns I've encountered:


zh ch sh merge with z c s (or distinguished at random):

Almost everywhere in the south, at least among most speakers

n merges with l (conditioned on following vowel):

Sichuan, Hunan, Hubei, Chongqing, Nanjing, ...

h merges with f (conditioned on following vowel):

Some Sichuan?, Hunan, Hubei, Chongqing

final n merges with final ng

Jiangsu, Shanghai

r merges with l

Jiangxi? I've met several people like this, and 2 were from Jiangxi.

Something about mixing up j q x versus the z c s and the g k:

Guangdong, HK