bug#49982: 27.2; ispell.el fails to find a Hunspell dictionary to use as default despite ispell-dictionary being set

[Eli Zaretskii <eliz@gnu.org>]

> From: Kisaragi Hiu <mail@kisaragi-hiu.com>
> Cc: 49982@debbugs.gnu.org
> Date: Wed, 11 Aug 2021 03:51:22 +0900
> 
> Thank you for the response! Let me try to add some clarifications (that 
> hopefully don't sound too harsh):
> 
>  > First, yours is an unusual use case, I think: when Hunspell is
>  > installed, the dictionary that corresponds to the locale is always
>  > installed, because otherwise Hunspell will not work reliably from the
>  > shell command line.
> 
> I'm fairly certain my use case isn't unusual.
> 
> There are no easily installable Hunspell dictionaries for, among other 
> languages:
> 
> - Any variant of Chinese (Mandarin)
> - Japanese
> - Kazakh
> - Khmer
> - Malay
> 
> Every user of any of these languages who tries to set up Hunspell
> along with ispell.el and Flyspell has to find or invent a poorly
> documented workaround.
> 
> - [[https://texwiki.texjp.org/?Hunspell][TeXJP (Japanese) mentions]] 
> "add[ing] the DICTIONARY or WORDLIST environment variables if needed" 
> (「また、必要に応じて環境変数DICTIONARYやWORDLISTを指定しておきます。」)
> - [[https://home.hirosaki-u.ac.jp/heroic-2020/1575/][Hirosaki University 
> Information Technology Center PC lab's tutorial to spellchecking in 
> Emacs]] sets DICTIONARY to en_US
> - 200ok.ch (developer of Organice)'s 
> [[https://200ok.ch/posts/2020-08-22_setting_up_spell_checking_with_multiple_dictionaries.html][tutorial 
> for using multiple dictionaries for Hunspell + ispell.el]] mentions

Indeed, defining DICTIONARY in the environment is the way to control
the default dictionary.  It is documented in the Hunspell's man page.
Why cannot it be the solution for when no Hunspell dictionary could be
found that matches the locale?  Using $DICTIONARY should solve your
problem both inside Emacs and outside it.