So similar to "tweelingen" in Dutch. Are there any other examples where "tvi" is used in words? I would have expected "to".
'tveegget', 'tvekjønnet' and 'tvetydig' are the most common ones I can think of. None others with 'tvi'.
"Tvil" means "doubt."
Why 'dere' and not du
Because "tvillinger" is plural.