I maybe wrong in understanding the documentation, but assuming I run the
following with a very recent "emacs -q" :

(setq ispell-process
      (apply 'start-process
             "ispell" nil
             "/usr/bin/hunspell"
            "-a"
            '("-d" "en_US" "-i" "UTF-8")))

(accept-process-output ispell-process 3)

The accept-process-output function should return a non-nil value, because
hunspell has output its banner (confirmed by associating a buffer to the
process). However I can't get it to report anything but nil, and this both
under Gnu/Linux and W32.

It doesn't work either if I set up a simple process filter.

Can someone enlighten me ?

Best regards,

-- 
Fabrice