Editing Igbo language (section)

===Vowels===
[[File:Igbo vowel chart.svg|thumb|The oral vowel phonemes of Igbo, based on {{Harvcoltxt|Ikekeonwu|1999}}]]
Igbo is a [[tone (linguistics)|tonal language]]. Tone varies by dialect but in most dialects there seem to be three register tones and three contour tones. The language's tone system was given by [[John Goldsmith (linguist)|John Goldsmith]] as an example of [[autosegmental]] phenomena that go beyond the linear model of [[phonology]] laid out in ''[[The Sound Pattern of English]]''.<ref>{{cite thesis |last=Goldsmith |first=John A. |date=June 1976 |title=Autosegmental Phonology |degree=Ph.D. |publisher=Massachusetts Institute of Technology. |url=http://www.ai.mit.edu/projects/dm/theses/goldsmith76.pdf |archive-url=https://web.archive.org/web/20050322005820/http://www.ai.mit.edu/projects/dm/theses/goldsmith76.pdf |archive-date=2005-03-22}}</ref> Igbo words may differ only in tone. An example is ''ákwá'' "cry", ''àkwà'' "bed", ''àkwá'' "egg", and ''ákwà'' "cloth". As tone is not normally written, these all appear as {{angbr|akwa}} in print.

In many cases, the two (or sometimes three) tones commonly used in Igbo dictionaries fail to represent how words actually sound in the spoken language . This indicates that Igbo may have many more tones than previously recognised. For example, the imperative form of the word ''bia'' "come" has a different tone to that used in statement ''O bia'' "he came". That imperative tone is also used in the second syllable of ''abuo'' "two". Another distinct tone appears in the second syllable of ''asaa'' "seven" and another in the second syllable of ''aguu'' "hunger".
[[File:WIKITONGUES- Valentine speaking Igbo.webm|thumb|Valentine speaking Igbo.]]
The language features [[vowel harmony]] with two sets of oral vowels distinguished by [[human pharynx|pharyngeal]] cavity size described in terms of [[retracted tongue root]] (RTR). These vowels also occupy different places in vowel space: {{IPA|[i ɪ̙ e a u ʊ̙ o ɒ̙]}} (the last commonly transcribed {{IPA|[ɔ̙]}}, in keeping with neighboring languages). For simplicity, phonemic transcriptions typically choose only one of these parameters to be distinctive, either RTR as in the chart on the right and Igbo orthography (that is, as {{IPA|/i i̙ e a u u̙ o o̙/}}), or vowel space as in the alphabetic chart below (that is, as {{IPA|/i ɪ e a u ʊ o ɔ/}}). There are also [[nasal vowel]]s.

Adjacent vowels usually undergo [[Assimilation (linguistics)|assimilation]] during speech. The sound of a preceding vowel, usually at the end of one word, merges in a rapid transition to the sound of the following vowel, particularly at the start of another word, giving the second vowel greater prominence in speech. Usually the first vowel (in the first word) is only slightly identifiable to listeners, usually undergoing [[Vowel reduction|centralisation]]. /kà ó mésjá/, for example, becomes /kòó mésjá/ "goodbye". An exception to this assimilation may be with words ending in /a/ such as /nà/ in /nà àlà/, "on the ground", which could be completely assimilated leaving /n/ in rapid speech, as in "nàlà" or "n'àlà". In other dialects however, the instance of /a/ such as in "nà" in /ọ́ nà èrí ńrí/, "he/she/it is eating", results in a long vowel, /ọ́ nèèrí ńrí/.<ref name="welmers74">{{cite book |last=Welmers |first=William Everett |year=1974 |title=African Language Structures |publisher=University of California Press |pages=41–42 |isbn=0520022106}}</ref>