Where does “gotchu” come from?

gotchu (English) comes from English Chu, from English You, from Middle English yow, from Old English ēow, from Proto-West Germanic iwwiz, from Proto-Germanic izwiz, from Proto-Germanic *jūz, from Proto-Indo-European túh₂ — you, thou.

Ancestry of “gotchu”, step by step

gotchu traces back through two separate lines of ancestry.

via English Chu

StepLanguageWordMeaning
1EnglishChuAn ancient Chinese viscounty and kingdom of the Zhou dynasty (circa 1030–223) along the Yangtze River
2EnglishYouHonorific alternative letter-case form of you,...
3Middle EnglishyowSecond-person plural object pronoun: you;...
4Old EnglishēowWo!, Alas!; sheep
5Proto-West Germaniciwwiz
6Proto-Germanicizwizaccusative/dative/instrumental of *jūz
7Proto-Germanic*jūz
8Proto-Indo-Europeantúh₂you, thou

via English got

StepLanguageWordMeaning
1Englishgotsimple past tense of get; past participle of get;...
Every word from Proto-Indo-European túh₂