apertium-destxt: 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-destxt - from package: apertium

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

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