←
Proto-Germanic *þū (inherited)
←
Proto-Indo-European *túh₂ (inherited)
←
Old Norse þú (inherited)
→
Icelandic þig (mention)
→
Icelandic áttu (mention)
→
Icelandic þúa (mention)
→
Icelandic þúa (mention)
→
Icelandic ertu (mention)
→
Icelandic þúst (mention)