если в настройках emacs flyspell-mode выключен, его можно включить 
M-x flyspell-mode

another description of this problem from
http://www.webservertalk.com/archive310-2005-3-983945.html

Hello,
I sometimes edit XML files with Emacs, using Mandrakelinux. After
editing a file, I used to launch M-x flyspell-buffer to spellcheck the
whole buffer at once, and then, after hiding XML tags (View -> Hide
Tags), I had a great and easy view of any mispelled word.

In its latest releases, aspell has become the default spell checking
system in Mandrakelinux. For some reason, this breaks - it seems -
flyspell's behaviour for "large regions" (i.e. when the buffer is larger
than the limit set in flyspell prefs, over which a separate ispell
process is normally launched): it just returns a "Can't check region" error.
I can increase the "large region" limit or simply disable it, so that
everything is always considered to be a "small region", but the process
is very slow this way, much more than it used to be: it takes several
minutes to highlight words in a moderately sized file, around 100
seconds for a small 4 kB file.
Maybe it would be faster if I could make it ignore XML tags.

Can anyone suggest a workaround for this, or any other solution to have
a global view of all mispelled words at once, with or without Emacs?

Thanks in advance.

--
Ciao,
Marco.
Linkage

прошу прощения, этот комментраий попал сюда по ошибке. 
это к emacs flyspell mode вместе с aspell.

=), а разница не велика, оно пересекается.. Да и мантайнер-то один =)

fixed in aspell 0.60.2