Editing Morphosyntactic alignment (section)

==Comparison between ergative–absolutive and nominative–accusative==
The arguments can be symbolized as follows:
* '''O''' = most patient-like argument of a transitive clause (also symbolized as '''P''')
* '''S''' = sole argument of an intransitive clause
* '''A''' = most agent-like argument of a transitive clause

The S/A/O terminology avoids the use of terms like "subject" and "object", which are not stable concepts from language to language. Moreover, it avoids the terms "agent" and "patient", which are semantic roles that do not correspond consistently to particular arguments. For instance, the A might be an experiencer or a source, semantically, not just an [[agent (grammar)|agent]].

The relationship between ergative and accusative systems can be schematically represented as the following:

{| class="wikitable"
!
! Ergative–absolutive
! Nominative–accusative
|-
| '''O'''
| {{color|#008000|same}}
| {{color|#800000|different}}
|-
| '''S'''
| {{color|#008000|same}}
| {{color|#008000|same}}
|-
| '''A'''
| {{color|#800000|different}}
| {{color|#008000|same}}
|}

The following [[Basque language|Basque]] examples demonstrate ergative–absolutive case marking system:<ref>Campbell, G. L. & King, G. (2011). ''The Routledge Concise Compendium of the World's Languages'' (2nd ed, p. 62). New York, NY: Routledge.</ref>

:{| cellpadding="6"
|+ '''Ergative Language'''
| {{interlinear|lang=eu
 |top=''Gizona etorri da.''
 |gizona{{color|#008000|'''-∅'''}} {etorri da}
 |the.man{{color|#008000|'''-ABS'''}} {has arrived}
 |{{color|#008000|'''S'''}} VERB<sub>intrans</sub>
 |'The man has arrived.'
}}
| &nbsp;&nbsp;&nbsp;&nbsp;
| {{interlinear|lang=eu
 |top=''Gizonak mutila ikusi du.''
 |gizona{{color|#800000|'''-k'''}} mutila{{color|#008000|'''-∅'''}} {ikusi du}
 |the.man{{color|#800000|'''-ERG'''}} boy{{color|#008000|'''-ABS'''}} saw
 |{{color|#800000|'''A'''}} {{color|#008000|'''O'''}} VERB<sub>trans</sub>
 |'The man saw the boy.'
}}
|}

In Basque, ''gizona'' is "the man" and ''mutila'' is "the boy". In a sentence like ''mutila gizonak ikusi du'', you know who is seeing whom because ''-k'' is added to the one doing the seeing. So the sentence means "the man saw the boy". If you want to say "the boy saw the man", add the ''-k'' instead to the word meaning "the boy": ''mutilak gizona ikusi du''.

With a verb like ''etorri'', "come", there's no need to distinguish "who is doing the coming", so no ''-k'' is added. "The boy came" is ''mutila etorri da''.

[[Japanese language|Japanese]] – by contrast – marks nouns by following them with different particles which indicate their function in the sentence:

:{| cellpadding="6"
|+ '''Accusative Language'''
| {{interlinear|lang=eu
 |top=''Kodomo ga tsuita.''
 |{kodomo {{color|#008000|'''ga'''}}} tsuita
 |{child {{color|#008000|'''NOM'''}}} arrived
 |{{color|#008000|'''S'''}} VERB<sub>intrans</sub>
 |'The child arrived.'
}}
| &nbsp;&nbsp;&nbsp;&nbsp;
| {{interlinear|lang=eu
 |top=''Otoko ga kodomo o mita.''
 |{otoko {{color|#008000|'''ga'''}}} {kodomo {{color|#800000|'''o'''}}} mita
 |{man {{color|#008000|'''NOM'''}}} {child {{color|#800000|'''ACC'''}}} saw
 |{{color|#008000|'''A'''}} {{color|#800000|'''O'''}} VERB<sub>trans</sub>
 |'The man saw the child.'
}}
|}

In this language, in the sentence "the man saw the child", the one doing the seeing ("man") may be marked with ''ga'', which works like Basque ''-k'' (and the one who is being seen may be marked with ''o''). However, in sentences like "the child arrived" ''ga'' can still be used even though the situation involves only a "doer" and not a "done-to". This is unlike Basque, where ''-k'' is completely forbidden in such sentences.