gvoice: command not found

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

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

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 CentOS possible default full paths are:

/usr/bin/gvoice - from package: python-googlevoice

You may install the required package with command yum install {package}

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