 The Igbo language was used by John Goldsmith as an example to justify deviating from the classical linear model of phonology as laid out in The Sound Pattern of English . It is written in the Roman script as well as the Nsibidi formalized ideograms , which is used by the Ekpe society and <unk> fraternity , but is no longer widely used . Nsibidi <unk> existed among the Igbo before the 16th century , but died out after it became popular among secret societies , who made Nsibidi a secret form of communication . Igbo language is difficult because of the huge number of dialects , its richness in prefixes and suffixes and its heavy intonation . Igbo is a tonal language and there are hundreds of different Igbo dialects and Igboid languages , such as the <unk> and <unk> languages . In 1939 , Dr. Ida C. Ward led a research expedition on Igbo dialects which could possibly be used as a basis of a standard Igbo dialect , also known as Central Igbo . This dialect included that of the Owerri and Umuahia groups , including the <unk> dialect . This proposed dialect was gradually accepted by missionaries , writers , publishers , and Cambridge University . 
