Small note, regarding English/German cognates with other Indo-European languages:

Unless you're dealing with a Latinism or Hellenism, distrust any potential cognate starting with the same stop or fricative. They almost never match, because of a bunch of really old sound changes that Proto-Germanic went through:

• PIE *p t ḱ k kʷ → PGerm *f θ h h hʷ
• PIE *b d ǵ g gʷ → PGerm *p t k k kʷ
• PIE *bʰ dʰ ǵʰ gʰ gʷʰ → PGerm *b d g g gʷ

Those changes are collectively known as Grimm's Law. (After Jacob Grimm - yup, the one from the fairy tales.)

So for example. If you find a Spanish word starting with /d/, and you want to find English cognates, don't look for English words also starting with /d/, but with /t/: dos/two, diez/ten, diente/tooth. Spanish "dia" for example does have an English cognate with /t/... and not much else - it's the /t/ in "lent" (from Proto-West-Germanic *langatīn spring - see that *tīn?).

If you try the opposite, you'll probably find Romance cognates with /f/ for English /d/. With Spanish then changing /f/→/h/→Ø, as in dough vs. heñir (to knead), both from PIE *dʰeyǵʰ- (to mould, form, build, knead).