Editing Serial comma (section)

==Ambiguity==
{{Further|Syntactic ambiguity}}
Omitting the serial comma may create ambiguity; writers who normally avoid the comma often use one to avoid this. Consider the [[wikt:apocryphal|apocryphal]] book dedication below:<ref>Based on example quoted in {{cite news|url=https://www.nytimes.com/2017/03/16/us/oxford-comma-lawsuit.html?_r=0|last=Victor|first=Daniel|title=Lack of Oxford Comma Could Cost Maine Company Millions in Overtime Dispute|newspaper=[[The New York Times]]|date=March 16, 2017|access-date=March 17, 2017|archive-date=March 17, 2017|archive-url=https://web.archive.org/web/20170317092502/https://www.nytimes.com/2017/03/16/us/oxford-comma-lawsuit.html?_r=0|url-status=live}}</ref>
:''To my parents, Mother Teresa and the pope.''
There is ambiguity about the writer's parentage as "Mother Teresa and the pope" can be read as an [[appositive phrase]] renaming of<ref>{{cite journal |last1=Emonds |first1=Joseph |title=Appositive Relatives Have No Properties |journal=Linguistic Inquiry |date=1979 |volume=10 |issue=2 |pages=211–243 |jstor=4178107 }}</ref> ''my parents'', leading the reader to believe that the writer claims that [[Mother Teresa]] and [[Pope|the pope]] are their parents. A comma before the ''and'' removes the ambiguity:
:''To my parents, Mother Teresa, and the pope.''
Nevertheless, lists can also be written in other ways that eliminate the ambiguity without introducing the serial comma, such as by changing the word order, or by using other or no punctuation to introduce or delimit them (though the emphasis may thereby be changed):
:''To the pope, Mother Teresa and my parents.''

An example collected by [[Patrick Nielsen Hayden|Nielsen Hayden]] was found in a newspaper account of a documentary about [[Merle Haggard]]:
:''Among those interviewed were his two ex-wives, [[Kris Kristofferson]] and [[Robert Duvall]].''<ref>{{cite web |url=http://nielsenhayden.com/makinglight/archives/012652.html |title=Making Light |publisher=Nielsenhayden.com |date=October 21, 2010 |access-date=February 10, 2013 |archive-date=January 22, 2013 |archive-url=https://web.archive.org/web/20130122013013/http://nielsenhayden.com/makinglight/archives/012652.html |url-status=live }}</ref>
A serial comma following "Kris Kristofferson" would help prevent this being understood as Kris Kristofferson and Robert Duvall being the ex-wives in question.

In some circumstances, using the serial comma can create ambiguity. If the book dedication above is changed to
:''To my mother, Mother Teresa, and the pope.''
the comma after ''Mother Teresa'' creates ambiguity because it can be read as an appositive phrase implying that the writer's mother is Mother Teresa. This leaves it unclear whether this is a list of three entities (1, my mother; 2, Mother Teresa; and 3, the pope) or of only two entities (1, my mother, who is Mother Teresa; and 2, the pope).<ref name=":0">{{Cite book|last=Adams|first=Kenneth A.|title=A Manual of Style for Contract Drafting|edition=3rd|publisher=American Bar Association|date=2013|at=12.61|isbn=978-1-61438-803-6}}</ref>

Also:
:''They went to [[Oregon]] with Betty, a maid, and a cook.''
This is ambiguous because it is unclear whether "a maid" is an [[appositive]] renaming of Betty or the second in a list of three people. On the other hand, removing the final comma:
:''They went to Oregon with Betty, a maid and a cook.''
leaves the possibility that Betty is both a maid and a cook (with "a maid and a cook" read as an appositive phrase).<ref>{{cite journal |last1=Delorme |first1=Evelyne |last2=Dougherty |first2=Ray C. |date=1972 |title=Appositive NP Constructions: We, the Men; We Men; I, a Man; Etc. |journal=Foundations of Language |volume=8 |issue=1 |pages=2–29 |jstor=25000571}}</ref> In this case, neither the serial-comma style—nor the no-serial-comma style—resolves the ambiguity. A writer who intends a list of three distinct people (Betty, maid, cook) may create an ambiguous sentence, regardless of whether the serial comma is adopted. Furthermore, if the reader is unaware of which convention is being used, both styles can be ambiguous in cases such as this.

These forms (among others) would remove the ambiguity:
* One person
** ''They went to Oregon with Betty, who was a maid and a cook.''
** ''They went to Oregon with Betty, both a maid and a cook.''
** ''They went to Oregon with Betty (a maid and cook).''
** ''They went to Oregon with Betty, their maid and cook.''
* Two people
** ''They went to Oregon with Betty (a maid) and a cook.''
** ''They went to Oregon with Betty—a maid—and a cook.''
** ''They went to Oregon with Betty, a maid, and with a cook.''
** ''They went to Oregon with the maid Betty and a cook.''
** ''They went to Oregon with a cook and Betty, a maid.''
* Three people
** ''They went to Oregon with Betty, as well as a maid and a cook.''
** ''They went to Oregon with Betty and a maid and a cook.''
** ''They went to Oregon with Betty, one maid and a cook.''
** ''They went to Oregon with a maid, a cook, and Betty.''
** ''They went to Oregon with a maid, a cook and Betty.''
** ''They went with Betty to Oregon with a maid and a cook.''

===In general===
* The list '''x, y and z''' is unambiguous if '''y and z''' cannot be read as a renaming of '''x'''.
* Equally, '''x, y, and z''' is unambiguous if '''y''' cannot be read as a renaming of '''x'''.
* If neither '''y''' nor '''y and z''' can be read as a renaming of '''x''', then both forms of the list are unambiguous, but if both '''y''' and '''y and z''' can be read as a renaming of '''x''', then both forms of the list are ambiguous.
* '''x and y and z''' is unambiguous if '''x and y''' and '''y and z''' cannot both be grouped.

Ambiguities can often be resolved by the selective use of semicolons instead of commas when more separation is required.<ref>{{cite journal |id={{ProQuest|237293138}} |last1=Watkins |first1=Ron |title=The Semicolon |journal=English Journal |volume=93 |issue=4 |date=March 2004 |page=22 |doi=10.2307/4128975 |jstor=4128975 }}</ref> General practice across style guides involves using semicolons when individual items have their own punctuation or coordinating conjunctions, but typically a "serial semicolon" is required.<ref>{{cite journal |last1=Bruthiaux |first1=Paul |title=The Rise and Fall of the Semicolon: English Punctuation Theory and English Teaching Practice |journal=Applied Linguistics |date=March 1995 |volume=16 |issue=1 |pages=1–14 |doi=10.1093/applin/16.1.1 }}</ref>