speech-dispatcher: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/speech-dispatcher - from package: speech-dispatcher

You may install the required package with command apt-get install {package}
Error in other languages:
speech-dispatcher: bevel nie gevind nie
speech-dispatcher: comandă negăsită
speech-dispatcher: comando não encontrado
speech-dispatcher: commande introuvable
speech-dispatcher: command not found
speech-dispatcher: käsku ei ole
speech-dispatcher: không tìm thấy lệnh
speech-dispatcher: komanda nerasta
speech-dispatcher: Kommando nicht gefunden.
speech-dispatcher: kommandot finns inte
speech-dispatcher: komut yok
speech-dispatcher: nie znaleziono polecenia
speech-dispatcher: níor aimsíodh an t-ordú
speech-dispatcher: no se encontró la orden
speech-dispatcher: no s'ha trobat l'ordre
speech-dispatcher: opdracht niet gevonden
speech-dispatcher: parancs nem található
speech-dispatcher: perintah tidak ditemukan
speech-dispatcher: príkaz nenájdený
speech-dispatcher: příkaz nenalezen
speech-dispatcher: команда не найдена
speech-dispatcher: командата не е открита
speech-dispatcher: 命令找不到
speech-dispatcher: コマンドが見つかりません