Is it right to use a verb in singular form for a noun in plural form as in “Your pigs is so much better than our pigs”?

I felt a bit puzzled to find the line “Your pigs is so much better than our pigs” in the following section of Jeffrey Archer’s novel Not a penny more, Not a penny less:

Harvey could never resist asking a policeman the way to Buckingham palace, just to compare his reaction with that of a New York cop. As Lenny Bruce had said on being deported from England, “Your pigs is so much better than our pigs.” Yes, Harvey liked England.

Microsoft Word spell-checker keeps warning me to correct “Your pigs is” as “Your pigs are” at this moment when I’m texting this question.

Is the spell-checker correct, or is the rule to use the singular form verb, “is” after the plural noun, “pigs"? Does it mean the verb in singular form should be used for the noun in plural form regardless of the rule of number agreement anytime the noun is used as a generic term or a collective noun?

Solution 1:

It is ungrammatical in Standard English, but other dialects have the same form of the verb be in the present tense for all persons. As well as is, it can in some cases be were and in others be.