Stefán Einarsson writes that, in Modern Icelandic, "The verbs binda,
standa, vinda and hrinda have bitt(u), statt(u), vitt(u), hritt(u) or
hrint(u) as imperatives. The verbs ganga and stinga have gakk or
gáttu, and stíktu. All other verbs [that] end in -nd and -ng retain
these sounds unchanged" (Icelandic: Grammar, Texts, Glossary 1945, In.
VII.4.6, Note 3).