The right first thing to do is to examine the letterforms and determine on structural grounds whether there is a case to be made for encoding.
Beesley claimed in 2002 that the glyphs used for EW [ju] and OI [ɔɪ] changed between 1855 and 1859. Well, OK. 1. The 1855 glyph for 𐐧 EW is evidently a ligature of the glyph for the diagonal stroke of the glyph for 𐐆 SHORT I [ɪ] and 𐐅 LONG OO [uː], that is, [ɪ] + [oː] = [ɪuː], that is, [ju]. 2. The 1855 glyph for 𐐦 OI is evidently a ligature of the glyph for 𐐉 SHORT AH [ɒ] and the diagonal stroke of the glyph for 𐐆 SHORT I [ɪ], that is, [ɒ] + [ɪ] = [ɒɪ], that is, [ɔɪ]. That’s encoded. Now evidently, the glyphs for the 1859 substitutions are as follows: 1. The 1859 glyph for EW is evidently a ligature of the glyph for the diagonal stroke of the glyph for 𐐆 SHORT I [ɪ] and 𐐋 SHORT OO [ʊ], that is, [ɪ] + [ʊ] = [ɪʊ], that is, [ju]. 2. The 1859 glyph for OI is evidently a ligature of the glyph for 𐐃 LONG AH [ɔː] and the diagonal stroke of the glyph for SHORT I [ɪ], that is, [ɔː] + [ɪ] = [ɔːɪ], that is, [ɔɪ]. If there is evidence outside of the Wikipedia for the 1859 letters, they should be encoded as new letters, because their design shows them to be ligatures of different base characters. That means they’re not glyph variants of the currently encoded letters. Michael Everson
