Following are a number of back-translations as well as a sample translation for translators of Isaiah 63:11:

• Kupsabiny: “So, his people remembered/thought about the days of old,
  the days of Moses.
  They asked one another/themselves, ‘Where is God,
  who saved people to pass through the sea/ocean
  together with their leaders?
  Where is God who gave his Spirit
  to come and stay in/with his people?” (Source: Kupsabiny Back Translation)
• Newari: “Then his people remembered the former days,
  the days of Moses and his people.
  The one who brought people with the shepherd of the flock from the sea — where did he go?
  The one who put the Holy Spirit in their midst — where is [he]?” (Source: Newari Back Translation)
• Hiligaynon: “But some-time later they have-remembered the past times which Moises caused- his people -to-come-out of Egipto. They asked, ‘Where is now the LORD who caused- us (incl.) -to-cross-over the sea together with our (incl.) leader/[lit. head] Moises who is like a shepherd of the sheep? Where is now the LORD who sent to us (incl.) his Holy Spirit?” (Source: Hiligaynon Back Translation)