sans parler de bedeutet auf Englisch

not to mention▼◼◼◼(much less)
conjunction

let alone▼◼◼◼(as well as)
conjunction
[UK: let ə.ˈləʊn] [US: ˈlet əˈloʊn]

let alone▼◼◼◼(to say nothing of)
conjunction
[UK: let ə.ˈləʊn] [US: ˈlet əˈloʊn]

to say nothing of▼◼◼◻(apophasis used to mention another important, usually related, point)
conjunction