They have weird ways. I had a cousin whose name was ‘Beauchamp’. It was pronounced ‘Beechum’. And the Italian name ‘Taliaferro’ wound up pronounced as ‘Tolliver’.
But according to them, we spell weirdly, so...
(My husband gets around the pronunciation issues surrounding the herb ‘basil’ by calling it ‘Mr. Rathbone’.)
Cholmondeley becomes Chumly. P. G. Wodehouse used to have fun making up names like Lord Blicester, or the Earl of Towcester.