vim spell checks

  :setlocal spell spelllang=en_us,de

Commands

  :spe {word}     add good word
  :spellw ...     add wrong word
  :spellra ...    add rare word

Keys

  ]s  [s        navigate misspelled words
                S (bad words), r (rare words)

  zg            mark as good word
  zw            mark as bad word
  zug, zuw      undo
  z=            suggest correct words / alternative

highlighting

  SpellBad
  SpellCap
  SpellRare
  SpellLocal