Following are a number of back-translations as well as a sample translation for translators of Isaiah 28:11:

• Kupsabiny: “God shall be speaking to them with/in the language of other people
  so that they can open/scoop/dewax their ears.” (Source: Kupsabiny Back Translation)
• Newari: “If it is like this, the LORD will speak [to you] by the mouths of foreigners
  and by people who speak a language [you] do not understand.” (Source: Newari Back Translation)
• Hiligaynon: “Because they would- not -listen, the LORD will-speak to these people through to those who-came-from different places with different language.” (Source: Hiligaynon Back Translation)