I have come across some American media (The Alternate History Hub youtube channel comes to mind) in which the perfect participle and the simple-past form have been merged.
For example, we would have:
- "We've driven there before" -> "We've drove there before"
- "I would've sunk" -> "I would've sank"
- "I've swum that distance before" -> "I've swam that distance before"
As far as I can tell, the replacement of the perfect with the simple past is consistent in this dialect, rather than just applying to some verbs (Edit in response to commment: with perhaps the exception of "to be" - "I have was ill" sounds odd enough that it would have really stood out).
Is this a feature of some American dialects? If so then in which? How common is this feature?
Related question (@sumelic): Is the past participle becoming obsolete? (I have went)