Nko uses 7seven [[diacritic]]al marks to denote [[tone (linguistics)|tonality]] and [[vowel length]]. Together with plain vowels, Nko distinguishes four tones: high, low, ascending, and descending; and two vowel lengths: long and short. Unmarked signs designate short, descending vowels. One dot below a vowel marks that vowel as nasal.<ref>{{Cite web |title=Chapter 19 – Unicode 16.0.0 |url=https://www.unicode.org/versions/Unicode16.0.0/core-spec/chapter-19/ |access-date=2025-03-26 |website=www.unicode.org |quote=When applied to a vowel, U+07F2 NKO COMBINING NASALIZATION MARK indicates the nasalization of that vowel. }}</ref>
