Following are a number of back-translations as well as a sample translation for translators of Isaiah 29:13:

• Kupsabiny: “God says,
  ‘These people say that they worship me
  but they only praise me with their mouths,
  and do not have me in the stomach/heart.
  Even if they pray to me, I shall not hear them,
  because their teaching only comes from where people are.” (Source: Kupsabiny Back Translation)
• Newari: “The LORD spoke like this,
  "These people will come near my place to show their faces.
  and with their mouths [they] give me much honor.
  With [their] hearts, however,
  they are staying very far [from me].
  They go on teaching people that the traditions they have made
  are God’s commands.” (Source: Newari Back Translation)
• Hiligaynon: “The Lord says, ‘These people are praising and honoring me with their mouth only, but their hearts are far from me. And their worshipping of me is only according to the regulation of man.” (Source: Hiligaynon Back Translation)
• English: “So the Lord says, ‘These people say that they belong to me.
  They honor me by what they say ,
  but they do not think about what I desire.
  When they worship me,
  all they do is recite rules that people have made and that they have memorized.” (Source: Translation for Translators)