St Kildan people spoke Gaelic. There are some Gaelic words which were only found on St Kilda. These came from the seabird harvest and included :

- lon - a climbing rope made of strips of plaited animal skin

- mogais - an anchor, made with heavy stones in a seal-skin sack

- crathadh - the usual way of killing a bird by dislocating its neck

- faire - literally 'nightwatch'. A hunter would wear dark clothes with a white cloth tucked under his throat. This way, he tricked razorbills coming in to roost on the islands at night into thinking he was another razorbill, so he could catch them.