Writing greek and arabic letters in memoir

Question

I'm trying to write a book (documentclass "memoir") and I would like each chapter to begin alternatively with a greek or arabic letter.

I have no problem with greek thanks to the package "babel", by contrast whatever attempt to write a-single-arabic-letter creates big conflicts in my template, such as compiling errors, and other problems (such as, the letter is automatically written on the right hand side: and it makes sense, of course, but I just need it as a symbol).

I've looked through many other questions, which usually concern writing sentences, and I wonder if there is a simpler method that fits my case.

Answer 1

If you’re trying to write a book, you are not submitting to the arXiv or a professor who still forces you to use legacy 8-bit fonts in 2023.

So compile with LuaLaTeX and use modern OpenType fonts. If all you need are single letters from another alphabet, you don’t even need to bother with Babel. Just declare your Arabic and (if necessary) Greek fonts with fontspec, such as \newfontfamily\arabicfont{Amiri}[Script=Arabic, Scale=MatchLowercase], and then write something like {\arabicfont ب}. (You can optionally \DeclareTextFontCommand\textarabic{\arabicfont} to be able to write \textarabic{ب}.)

If you want to use the letters in math mode, I recommend loading unicode-math and writing something like

\newcommand\mathbah{\mathord{\textup{\textarabic ب}}}