Opinions vary regarding the use of apostrophes when forming the plurals of letters of the alphabet. New Fowler's Modern English Usage, after noting that the usage has changed, states on page 602 that "after letters an apostrophe is obligatory." The 15th edition of The Chicago Manual of Style states in paragraph 7.16, "To avoid confusion, lowercase letters ... form the plural with an apostrophe and an s". The Oxford Style Manual on page 116 advocates the use of common sense.
1 Used in Old Egyptian; archaic by Middle Egyptian. 2 Used mostly since Middle Egyptian. 3 Archaic or greatly restricted in usage by Middle Egyptian. The perfect has mostly taken over the functions of the perfective, and the subjunctive and periphrastic prospective have mostly replaced the prospective. 4 Declines using third-person suffix pronouns instead of adjectival endings: masculine .f/.fj, feminine .s/.sj, dual .sn/.snj, plural .sn.
5 Only in the masculine singular. 6 Only in the masculine. 7 Only in the feminine.
James P[eter] Allen (2010) Middle Egyptian: An Introduction to the Language and Culture of Hieroglyphs, 2nd edition, Cambridge: Cambridge University Press, →ISBN, pages 105, 115, 273.
