Glottal-stopped

And in a heavy London Cockney "That's all right, isn't it?" becomes "aess aw roy? ni?" with both the "t" in "right" and "it" glottal stopped.

Source: wiktionary

Throughout Back to Black, her glottal-stopped London accent eerily combines with a Motown swing in the phrasing, each element undercutting and enhancing the other to make a smooth-rough-smooth sound that’s classic and yet also speaks of its particular moment.

Source: wiktionary