So we should all have national anthems which don't offend anyone? That should be fun.

Derry/Londonderry is known in Irish as Doire Cholm Cille - St Columbkill's Oakwood, or possibly St Columbkill's Church, as Doire usually refers to a holy oakwood, and these were usually taken over by the Christians as their holy sites.

Doire is pronounced (roughly) Dirruh, which in English became Derry.

At some stage this was transmuted to Londonderry when a bunch of Londoners came in, as I understand, ushered by one or another English royal eager to improve Ireland by making it more English with the help of 'planters' - English, Welsh or Scottish settlers moved on to land confiscated from Irish owners.