Following are a number of back-translations as well as a sample translation for translators of Isaiah 30:21:

• Kupsabiny: “When you (plur.) go to the right
  or to the left,
  you shall hear it being said behind (you),
  ‘This is the road, follow (it).’” (Source: Kupsabiny Back Translation)
• Newari: “When you go right or left, [you] will hear a voice behind you speaking like this, "This is the way, go in this one."” (Source: Newari Back Translation)
• Hiligaynon: “and you (plur.) will-hear his voice guiding you (plur.) to the right path, anywhere you (plur.) are.” (Source: Hiligaynon Back Translation)
• English: “And you will hear him speak to you to guide you. Right behind you he will say, ‘This is the road on which you should walk; walk on this road!’” (Source: Translation for Translators)