Download a pair of spellfiles and convert them to Vim's

update-academic-spelling.sh

#!/bin/sh

# Adapted from:
# https://github.com/ficcdaf/academic.nvim/blob/83865969059b2aaea2e7afcebaa60085e965d9f8/scripts/generate-wordlist.sh

# Adjust to your home directory:
VIM_HOME="$HOME/.vim"
DOWNLOAD_TARGET="$VIM_HOME/spell/en-academic"

# The "unmunch" command comes with "hunspell":
unmunch <(curl -s https://raw.githubusercontent.com/emareg/acamedic/refs/heads/master/en-Academic.dic) \
  <(curl -s https://raw.githubusercontent.com/emareg/acamedic/refs/heads/master/en-Academic.aff) \
  > "$DOWNLOAD_TARGET"

# You can also run this `mkspell!` command directly in Vim:
echo "mkspell! $DOWNLOAD_TARGET" | vim -es

# This will create `~/.vim/spell/en-academic.utf8.spl`. To use it, add it to `spellang`:
# set spellang=en,en-academic