If you have the libraries needed add the --with-pspell[=dir] option when compiling PHP.
Note: Note to Win32 Users
为了使此扩展生效， DLL 文件必须能在 Windows 系统的 PATH 指示的路径下找到。如何操作的信息，请参见题为“如何在 Windows 中将 PHP 目录加到 PATH 中”的FAQ。虽然将 DLL 文件从 PHP 文件夹复制到 Windows 系统目录也行，但不建议这样做。 此扩展需要下列文件在 PATH 路径中： aspell-15.dll from the bin folder of the aspell installation.
Win32 support is available only in PHP 4.3.3 and later versions. Also, at least aspell version 0.50 is required.
juliusdavies at gmail dot com (2009-03-18 16:06:27)
Aspell + PHP + Windows was giving me just crazy crashes with this simple test file:
<?php
$pspell_link = pspell_new("en");
?>
Running "php -f test.php" directly from a DOS prompt shed some light:
----------------
The file "C:\Program Files\Aspell\data/iso8859-1.dat" can not be opened for reading.pell\dict/en-only.rws:
----------------
To fix it I needed to "dos2unix" all the files in Aspell's C:\Program Files\Aspell\data\ directory. (Convert them from CRLF to just LF line endings).