Hi Tiger, These constructions normally reflect a very specific English dialect e.g., African American Vernacular or English commonly used in a specific region. As others have mentioned, you could say that this person is poorly educated or is using English in a very casual context. The examples that you provided are technically linguistically grammatically correct, i.e., these grammatical constructions do exist in according to descriptivists. However, according to prescriptivists - those who believe that standard grammar is the correct way to express something in any context - argue that these constructions are incorrect in every way.

Here's what it doesn't mean: It does not mean that they are making a mistake. As Wenwei says, "these grammatical constructions do exist [according to descriptivists]. " Descriptivists focus on the way that language is really spoken and written. The millions of native English speakers who say 'He don't' or 'He ain't got no ...'. are not getting their grammar wrong. These non-standard constructions actually form part of the 'grammar' of particular variants/dialects of English. Who speaks like this? Well, we all do sometimes. At one end of the scale, you have people (usually less well-educated people) who always use these non-standard forms. They have grown up in an environment where everyone around them says 'He don't', so that is simply the dialect of English which they speak. At the other end of the scale, even highly educated people sometimes use non-standard grammar in a playful way, or in a quote or catchphrase such as 'You ain't seen nothing yet'. And in the middle, there are all sorts of people who chose to use non-standard grammar in some contexts but not in others: Songwriters generally choose to use the 'He don't..' form in song lyrics for both practical reasons ( it's easier to sing and fits better with the rhythm patterns of most lyrics) and cultural reasons ( it may sound more down-to-earth and heartfelt, or more rebellious and subversive - think of Pink Floyd's "We don't need no education"). Sometimes people code-switch to fit in socially. A successful London businessperson from a modest background will use 'correct' verb forms at work, but will switch to saying 'You was' and 'He don't' when he's down the local pub with his old schoolmates. As you can see, there are many reasons why we use non-standard grammar. The only thing to remember is it is never a mistake.

It could mean several things. It could mean that the native speaker is poorly educated and doesn't speak very correctly. It could mean that they are speaking in a way that is typical of the casual usage in their locality. It could mean that they are playing with the language in a poetic way. But it probably doesn't convey any difference of meaning in the words.

Su.Ki. gave a wonderful answer. Codeswitching is the technical term. People switch between their home/neighbourhood dialect and the prestige/broadcast/education "standard" dialect when needed. Racists and xenophobes often use dialect differences as "evidence" of the inferiority of people who are different. I live next to a francophone university in a mixed anglophone/francophone region. The local dialect is "non-standard French" (bad French to the purists) but the university students easily switch between the local dialect and standard French depending on the social context. They are not stupid, lazy, or uneducated. I lived in the US for 40 years. I saw black coworkers codeswitching between "white English" at the office and "black English" (African-American Vernacular English) on phone calls to family members. Wikipedia article: https://en.wikipedia.org/wiki/African-American_Vernacular_English

What does it mean when native speakers use basic grammar incorrectly in spoken language? A poor education or the place where you live can effect your grammar.