младенчество означает в английский

babyhood▼(state or period of infancy)
noun
[UK: ˈbeɪ.bi.hʊd] [US: ˈbeɪ.bi.ˌhʊd]

diaperhood▼(period of wearing diapers)
noun

infancy [infancies]▼(earliest period of childhood)
noun
[UK: ˈɪn.fən.si] [US: ˈɪn.fən.si]