What's With the Extra Is?

Increasingly, you hear people these days using the construction is, is in sentences. 

What it is, is a new way of talking. 

The best way to think of what it is, is by imagining that people aren't hearing what they're actually saying.

Is you dumb, or is you just careless?

Is you is, or is you not, my baby? 

Ungrammatical constructions are one thing--offered as playful wit, they can be cute. Speaking awkwardly out of carelessness, though, can be irritating. 

Technically, What it is, is is not an ungrammatical construction. But why begin a sentence in this way, when it makes more sense simply to say It is followed by the object? What it is has become a lazy way many people have of starting sentences, like That said or Hey or You know what? 

A lot of conversational speech consists of such place-holders, which are nothing more than postponements of sense, or habitual interjections that persist like nervous verbal tics in the stream of speech. 

Everyone knows how frustrating it is to listen to someone who cannot say more than three consecutive words in sequence without interjecting uhh, or you know.

What most astonishes me is that people will defend their use of bad (or sloppy) grammatical constructions, as if it were their right to do so.  "Everyone says that," they will say, or "everyone knows what it means." 

Everyone knows what "ain't" means, but using it is still wrong.

Everyone knows--or should--that nu-kee-lor is a mispronunciation of nuclear. Yet people continue to punish the word by willfully abusing it. 

Everyone knows--or should--that you don't lay [yourself] down, you lie down.

There is a kind of patent permission that evolves out of lazy or ignorant usage. People who want an excuse or a pretext for their own failures, will rely on the popularity of illiteracy for support. 

Is there anything dignified or honorable about relying on other people's ignorance to defend your own?