Why is it that when doing "german accent english", people often say "za" in place of "the" when german uses "der, die, das"? Where did the "z" even come from?

@JohnZhau The th sounds are not part of standard German pronunciation and thus many Germans never learn how to produce them. Instead, they will emulate these sounds with a voiced or unvoiced s sound, respectively. Since the begins with a voiced th, this leads to a voiced s sound in emulation, which in turn is usually rendered with z in English orthography.

So this part is realistic.