The functions needed doesn't exist in Speex 1.05 which is what a lot of distros use.
1.2 seems to have been in beta status for years, and does include the sexy functions needed for func_speex to work.
git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@227237
65c4cc65-6c06-0410-ace0-
fbb531ad65f3
*
* \ingroup functions
*
- * \extref The Speex library - http://www.speex.org
+ * \extref The Speex 1.2 library - http://www.speex.org
+ * \note Requires the 1.2 version of the Speex library (which might not be what you find in Linux packages)
*/
/*** MODULEINFO