apertium-lextor: 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 Debian possible default full paths are:

/usr/bin/apertium-lextor - from package: apertium

You may install the required package with command apt-get install {package}

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