Orejón language
Orejón (Oregon), also Coto or Maijiki, is a moribund Tucanoan language of Peru. Writing system

The letters  can also be written as  in the National Register of Identity and Civil Status of Peru. Nasal vowels have an underlined stroke and tones are indicated using diacritics:
 low-tone vowels with the grave accent ;
 high-tone vowels with the acute accent ;
 low-tone nasal vowels with the macron below and grave accent ;
 high-tone nasal vowels with the macron below and acute accent . References

Languages of Peru
Tucanoan languages