The Glynnese Glossary is that rare beast, a dictionary of a family language. Many families develop favourite words and phrases, giving them unique meanings based on passing events or encounters. For the most part these fade into oblivion with the death of their users. The families of William Gladstone, several times Prime Minister of England, and of his wife Catherine Glynne, however, developed an unusually rich and persistent language; and this was recorded in the Glossary in 1851 by Gladstone’s brother-in-law George, Lord Lyttelton, who married Catherine Glynne’s sister Mary. Glynnese can be traced through generations of family memoirs, and the families’ lofty social status led to its being taken up by outsiders. Lyttelton was a talented student of language, and in the Glossary he draws on the contemporary popularity of philology to produce a spoof dictionary which parodies the tradition of dialect glossaries, while accurately recording the eccentric vagaries of Glynnese. George William, 4th Baron Lyttelton (1817-76) was educated at Eton and at Trinity College, Cambridge, where he was Senior Classic (top of the first class in Classics) in 1838. In 1839 he and William Gladstone married the sisters Mary and Catherine Glynne in a double wedding conducted by the brides’ father. He had eight sons and four daughters, and a further three daughters by his second wife. Lyttelton and Gladstone were both keen composers in Latin and Greek, and published a book of translations from English literature together in 1861. Lyttelton devoted much of his life to public service, especially in education, sitting on two Royal Commissions in the 1860s. He was a manic depressive, and committed suicide in 1876.