Following are a number of back-translations as well as a sample translation for translators of Isaiah 29:4:

• Kupsabiny: “You shall be pulled down to the ground,
  there in/at the soil where you shall speak from.
  You shall only be whispering there in the soil
  the throat speaking faintly like a ghost/spirit.” (Source: Kupsabiny Back Translation)
• Newari: “You are about to be pushed down below,
  then from the earth [you] will speak, From the out of the dust will come your unintelligible words.
  Your voice will come like a ghost from the earth.
  And your whispering voice will come from the dust.” (Source: Newari Back Translation)
• Hiligaynon: “She will-be-destroyed, and will-be like a ghost calling from the deep of the ground, whose voice is muffled.” (Source: Hiligaynon Back Translation)
• English: “Then you will talk as though you were buried deep in the ground ;
  it will sound like someone whispering from under the ground,
  like a ghost speaking from a grave.” (Source: Translation for Translators)