I came across this mess
http://www.woxikon.com/swe/gn%E4gga.php
French hennir
Dutch hinniken
Italian nitrire
Swedish gnägga
DEO:
No. kneggja
Icel. hneggja
OE hnægan
Engl. neigh
and (?)
Spanish, Portuguese relinchar (? < *-ninch-)
Is there any way to connect them?
Torsten