The line "We goin' keep on dancing" is a casual, colloquial way of speaking, often found in lyrics or informal speech. It's not grammatically standard, as "goin'" is a shortened, informal form of "going." The grammatically correct version would be: "We're going to keep on dancing." However, the informal version is acceptable in music and casual conversation, where slang and relaxed grammar are common.

I think the others found the answer. FYI, lyrics are often grammatically incorrect. It's nice to be able to understand them, but you wouldn't necessarily want to use them as models for how to speak English.

I believe you might have heard this sentence, "We're gonna keep on dancing". Here, "gonna" is a colloquial contraction for "going to," and "we're" is the contraction for "we are."

No, correctly would be "we're going to keep on dancing", or "we're goin' to keep on dancin'."

What you heard was probably We Gon' Keep On Dancin' which is a line from the song Crazy Kids by Kesha. Gon' is a contraction of Gonna which itself is a contraction of Going To. And in slang speech, We Are Gonna is often shortened to We Gonna (with Are omitted), thus We Gon' Keep On Dancin' is a grammatically valid slang phrase meaning We Are Going To Keep On Dancing which is how it would be said in a formal tone.