Friendly heads up - this isn't a word, and also happens to be one of those slip-ups that people will judge you extra hard for. Say either "regardless" or "irrespective".
Feel free to disregard my advice, though; it's no skin off my nose if you don't want to sound like a "native, educated speaker".
>We label irregardless as “nonstandard” rather than “slang.” When a word is nonstandard it means it is “not conforming in pronunciation, grammatical construction, idiom, or word choice to the usage generally characteristic of educated native speakers of a language.” Irregardless is a long way from winning general acceptance as a standard English word. For that reason, it is best to use regardless instead.
Like I said - I really don't care what you do. I'm just trying to be helpful. Use "irregardless" and people will judge you. If you want to die on that hill, be my guest.
The problem is that you think trying to sound smart by interrupting a conversation with irrelevant factoids is a "good deed". Maybe some introspection is appropriate here.
A word is a thing people say. If you say irregardless to somebody you're trying to impress, you will fail to.
A friendly correction of a non-standard word does not deserve derision.