"tiong-ng" (middle)

[hong]

one dict says ?h baidu-ng1 wendu-un7.So my problem is solved .Another ?Z =摇动(yan)baidu-ng2 wendu-un2.Maybe 掩 case is like the last one.
I find that one minnan dict give my surname 王 baidu as ng5,wendu as ong5 and 7.I know that we should use baidu for surname but wendu for name.Why this is not the case?

[hong]

I just found one xiamen dict say 掩 bai-im wen-iam but no ng is mentioned as baidu.

[Andrew Yong]

Hong: ong5 is both literary and colloquial; ng5 is only colloquial in a few phrases.

[hong]

ng-tng 怏??---叛逆(rebel),??扭,?剔?ngo-gek忤逆 also the same