How is non-standard Cantonese spoken by some mainland Chinese speakers different from "standard" pronunciation? As someone who's more or less a native Cantonese speaker, I've noticed that some speakers from mainland China (from Cantonese speaking areas) sound "weird", in that I could clearly notice a difference between them and Hong Kong speakers.

Unfortunately, I can't find a video on YouTube of some examples, but I know of Cantonese speakers from Hong Kong who attribute this to "鄉音". (I have most definitely seen something of the sort on some Hong Kong news channels before, but it's difficult to locate any specific clips.)

Is there anything that generally characterizes these deviations from the sort of Cantonese that might be spoken by Hong Kongers or is the potential "鄉音" influence impossible to generalize? (Some link to another analysis on the internet could also come in handy.)

This would seem relevant, but the difference I'm interested in is more of the difference between a subset of mainland speakers and other Cantonese speakers. For what it's worth, I have not seen the same differences among Chinese American Cantonese speakers with family from mainland China, and I know of mainland Chinese who essentially speak "properly". I am also not sure if this is a non-native speaker problem, particularly in areas like Shenzhen where Mandarin might be more heavily used. But at the very least, note that I am interested in non-standard pronunciation among some mainland Chinese in Cantonese speaking areas, and not, say, a Beijing Mandarin-speaker who knows some Cantonese.
Edit: Sorry that I misunderstood the question.  I thought Maroon was talking about non-native Cantonese speakers.



Most native Mandarin speakers have trouble handling the rising (上聲) and departing tones (去聲) in Cantonese.  It is because Cantonese further differentiates them into high-rising (陰上), low-rising (陽上), high-level (陰去) and low-level (陽去).  (Please refer to http://zh.wikipedia.org/wiki/%E5%9B%9B%E8%81%B2#.E7.8E.B0.E4.BB.A3.E6.96.B9.E8.A8.80.E5.A3.B0.E8.B0.83.E5.AF.B9.E7.85.A7 for the exact tone contours.)

They also have difficulties pronouncing checked tones (入聲) as they are also absent from Mandarin.  And, again, there are three levels of checked tones (陰入, 中入 and 陽入), making it even more difficult to manage.