Where does “iu” come from?

iu (Old Dutch) comes from Proto-West Germanic iwwiz, from Proto-Germanic izwiz, from Proto-Germanic *jūz, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “iu”, step by step

StepLanguageWordMeaning
1Proto-West Germaniciwwiz—
2Proto-Germanicizwizaccusative/dative/instrumental of *jūz
3Proto-Germanic*jūz—
4Proto-Indo-Europeantúh₂you, thou
Every word from Proto-Indo-European túh₂ →Every word from Proto-Germanic *jūz →Every word from Proto-Germanic izwiz →