ispell personal dictionary for multiple languages

Question

I use hunspell for spellchecking. When I switch dictionaries (e.g., from en_US to hu_HU), I cannot save personal words to my personal dictionary. Emacs complains that

ispell-init-process: Error: Expected language "hu" but got "en".

I assume that's because the value of ispell-personal-dictionary is ~/.aspell.en.pws, and the first line of that file is personal_ws-1.1 en 46. Maybe I should not use aspell's personal dictionary for hunspell, but when I set ispell-personal-dictionary to a new (empty) file, the message I get

ispell-init-process: Error: The file "[filename]" is not in the proper format.

(Hunspell personal dictionaries are supposed to be simple word lists, according to the man page.)

1. How can I set up separate personal word lists for different languages?

2. What is the format for a hunspell personal dictionary?

(+1. Incidentally, to make sure I run hunspell, I added ispell-program-name (executable-find "hunspell") to my .emacs, which resulted in

split-string: Wrong type argument: stringp, nil

hunspell does run, but only if ispell-program-name is not set.)