Here’s an example of someone who is very accomplished and articulate with a high school education but whose control of standard verb forms is erratic, viz. doand have vs known. The lack of a d on experienced may or may not reflect a phonetic dropping of a final consonant but likely not an actual realization of a past participle without a final d.
“The guy that I brought in do not seem to be the right fit so I am looking at another guy. The new guy is good but do not have the experience the other guy have. I have to figure out how to move the experience guy out (someone I have known for 25 years or so)”
I’ve listened to this person for the last 57 years so I can say this reflects his normal speech in all circumstances. Y-===

Now here is non-English as found on a fraudulent request for information:

Your User ID requires to be Fixed

hello, do what we asked you now.

The first is ungrammatical, the second one violates pragmatic rules.