Igbo is a language spoken in Nigeria by around 18 million speakers (the Igbo), especially in the southeastern region once identified as Biafra. The language was used by John Goldsmith as an example to justify going away from the classical linear model of phonology as laid out in The Sound Pattern of English. It is written in the Roman script. Igbo is a tonal language, like Yoruba and Chinese. Most Igbo people prefer that the language be spelled Igbo rather than Ibo.