Langran Family History

Unexplained; possibly from a Middle English lange rane ‘frog's tongue’ parallel to lange serpent ‘snake's tongue’ ‘a tongue-shaped stone having the property of detecting poison’. In MED ranula ranule ‘abscess under the tongue’ is exemplified in about 1425 thus: ‘Ranula..is a maner carnositee oblong vnder þe tonge lettyng þe acte of it to þe fourme of a rane i. froske.’

The surname may therefore be a nickname for someone with such an abscess.