Following are a number of back-translations of Mark 9:29:
Uma: “He said to them: ‘Evil-spirits like that cannot be expelled with any knowledge whatsoever, only with prayer.'” (Source: Uma Back Translation)
Yakan: “He said to them, ‘That kind of demon cannot be cast out by anything except only if asked of God.'” (Source: Yakan Back Translation)
Western Bukidnon Manobo: “And Jesus answered, he said, ‘That kind of demon cannot be driven away except by prayer, for there is no other way.'” (Source: Western Bukidnon Manobo Back Translation)
Kankanaey: “‘An evil-spirit like that, it doesn’t leave if the one causing-it -to-leave doesn’t pray to God,’ said Jesus answering.” (Source: Kankanaey Back Translation)
Tagbanwa: “Jesus replied, saying, ‘That kind of evil spirit can’t be driven out without perseverance/much-effort in prayer.'” (Source: Tagbanwa Back Translation)