Editing Dialect (section)

=== Dialect and language clusters ===
{{See also|Dialect continuum}}
In other situations, a closely related group of varieties possess considerable (though incomplete) mutual intelligibility, but none dominates the others. To describe this situation, the editors of the ''Handbook of African Languages'' introduced the term '''dialect cluster''' as a classificatory unit at the same level as a language.<ref>{{cite journal
  | title = A Handbook of African Languages
  | author = Handbook Sub-committee Committee of the International African Institute.
  | journal = Africa | volume = 16 | number = 3 | year = 1946 | pages = 156–159
  | doi = 10.2307/1156320
 | jstor = 1156320
| s2cid = 245909714
 }}</ref> A similar situation, but with a greater degree of mutual unintelligibility, has been termed a '''language cluster'''.<ref>{{cite journal
  | title = A provisional language map of Nigeria
  | given1 = Keir | surname1 = Hansford
  | given2 = John | surname2 = Bendor-Samuel
  | given3 = Ron | surname3 = Stanford
  | journal = Savanna | volume = 5 | number = 2 | year = 1976 | pages = 115–124
}} p. 118.</ref>

In the ''Language Survey Reference Guide'' issued by [[SIL International]], who produce ''[[Ethnologue]]'', a ''dialect cluster'' is defined as a central variety together with a collection of varieties whose speakers can understand the central variety at a specified threshold level (usually between 70% and 85%) or higher. It is not required that peripheral varieties be understood by speakers of the central variety or of other peripheral varieties. A minimal set of central varieties providing coverage of a dialect continuum may be selected algorithmically from intelligibility data.<ref>{{cite book |title=Language Survey Reference Guide |first=Joseph Evans |last=Grimes |publisher=SIL International |year=1995 |isbn=978-0-88312-609-7 |pages=17, 22 }}</ref>