Vowels are separated into low, rising, and high categories, which are presumably the only tonal delineations in Igbo. The notable absence of a corresponding “falling” tone, I first thought, creates problems for adapting the script to a language like Yorùbá, where, for example, the ọ̀ in Báyọ̀ carries a “falling” rather than a “low” tone when the sound is properly rendered. But on a second look, I find that what is meant as “rising” here is actually the same as a “mid” tone in Yorùbá. Still, linguists interested in adapting Ńdébé for languages with different tonal patterns than Igbo’s, or with no tone at all, like Fulfulde, have plenty to work with. Igwe-Odunze, who has been working on this writing system for over ten years, has been clear that her original intention was to provide an Igbo script, calling Ńdébé her “gift to every Igbo person.”

— Writing Africa’s Future in New Characters, Kọ́lá Túbọ̀sú in Popula