[Spellyans] lyver ~ lever

[Nicholas Williams]

It would seem from the texts that lever rather than lyver is the default form of the word for 'book' in MC:

levar PA 135d 
liuer BM 101 ~ lefer BM 1418, BM 1499
lyver TH 6a, TH 42, TH 45a, TH 47a, TH 49a, 60; lyfer TH 45; lyuer TH 18a, TH 55 ~ levarTH 56a, 
levar SA 59

The spelling lyver is not actually attested until TH. 

The vowel is similar to that of screfa/scryfa, gwetha/gwytha, trega/tryga, teller/tyller. Short i in open syllables in polysyllables is in free variation with short e. There is no need to insist on spelling variants.

Compare also kenyver ~ keneffra (which the SWF spells keniver — a form confined to one instance in Late Cornish).

Nicholas