In generative grammar and related frameworks, a node in a parse tree c-commands its sister node and all of its sister's descendants. In these frameworks, c-command plays a central role in defining and constraining operations such as syntactic movement, binding, and scope. Tanya Reinhart introduced c-command in 1976 as a key component of her theory of anaphora. The term is short for "constituent command".
Definitions and examples
Common terms to represent the relationships between nodes are below (refer to the tree on the right):
- M is a parent or mother to A and B.
- A and B are children or daughters of M.
- A and B are sisters.
- M is a grandparent to C and D.
The standard definition of c-command is based partly on the relationship of dominance: Node N1 dominates node N2 if N1 is above N2 in the tree and one can trace a path from N1 to N2 moving only downwards in the tree (never upwards); that is, if N1 is a parent, grandparent, etc. of N2. For a node (N1) to c-command another node (N2) the parent of N1 must establish dominance over N2.
Based upon this definition of dominance, node N1 c-commands node N2 if and only if:
- Node N1 does not dominate N2,
- N2 does not dominate N1, and
- The first (i.e. lowest) branching node that dominates N1 also dominates N2.
For example, according to the standard definition, in the tree at the right,
- M does not c-command any node because it dominates all other nodes.
- A c-commands B, C, D, E, F, and G.
- B c-commands A.
- C c-commands D, F, and G.
- D c-commands C and E.
- E does not c-command any node because it does not have a sister node or any daughter nodes.
- F c-commands G.
- G c-commands F.
If node A c-commands node B, and B also c-commands A, it can be said that A symmetrically c-commands B. If A c-commands B but B does not c-command A, then A asymmetrically c-commands B. The notion of asymmetric c-command plays a major role in Richard Kayne's theory of Antisymmetry.
Reinhart's definition, one of the earlier definitions on this concept, is based partly on the relation of immediate dominance: Node N1 immediately dominates node N2 if N1 is above N2 in the tree and there is no node in between N1 and N2; that is N1 dominates N2 and there is no node dominating N2 that does not dominate N1 because there is no other node between N1 and N2.
Based upon this definition of immediate dominance, node N1 c-commands node N2 if and only if the branching node X1, immediately dominating N1, either:
- Dominates N2 , or
- Is immediately dominated by node X2 which dominates N2 (where X1 and X2 are of the same category)
According to Reinhart's definition, a node can c-command itself, sister nodes can c-command each other, and c-command relations involving X’ over X (as in X-bar Theory) can be represented. For example, according to Reinhart's definition, in the tree at the right,
- Z does not c-command any node because there is no node immediately dominating it.
- Y c-commands Y, X2, W, X1, V, U, T.
- X2 c-commands Y, X2, W, X1, V, U, T.
- W c-commands W, X1, V, U, T.
- X1 c-commands W, X1, V, U, T.
- V does not c-command any node because W, immediately dominating V, is not a branching node.
- U c-commands W, V, U, T.
- T c-commands W, V, U, T.
The term c-command was introduced by Tanya Reinhart in her 1976 dissertation and is a shortened form of constituent command. Reinhart thanks Nick Clements for suggesting both the term and its abbreviation. However, the concept Reinhart was developing was not new to syntax. Similar configurational notions had been circulating for more than a decade. In 1964, Klima defined a configurational relationship between nodes he labeled "in construction with". In addition, Langacker proposed a similar notion of "command" in 1969.
Criticism and alternatives
The validity and importance of c-command for the theory of syntax is debated. In most cases, c-command correlates with precedence (linear order); that is, if node A c-commands node B, it is usually the case that node A also precedes node B. Furthermore, basic S(V)O (subject-verb-object) word order in English correlates positively with a hierarchy of syntactic functions, subjects precede (and c-command) objects. Moreover, subjects typically precede objects in declarative sentences in English and related languages. Bruening (2014) argues that theories of syntax that build on c-command have misconstrued the importance of precedence and/or the hierarchy of grammatical functions (i.e. the grammatical function of subject versus object). He concludes that what c-command is intended to address is more accurately analyzed in terms of precedence and grammatical functions. Further, the c-command concept was developed primarily on the basis of syntactic phenomena of English, a language with relatively strict word order. When confronted with the much freer word order of many other languages, the insights provided by c-command are less compelling, since linear order becomes less important.
As just suggested, the phenomena that c-command is intended to address may be more plausibly examined in terms of linear order and a hierarchy of syntactic functions. Concerning the latter, some theories of syntax take a hierarchy of syntactic functions to be primitive. This is true of Head-Driven Phrase Structure Grammar (HPSG), Lexical Functional Grammar (LFG), and dependency grammars (DGs). The hierarchy of syntactic functions that these frameworks posit is usually something like the following: SUBJECT > FIRST OBJECT > SECOND OBJECT > OBLIQUE OBJECT. Numerous mechanisms of syntax are then addressed in terms of this hierarchy.
- Terms to represent the relationships between nodes is taken from Sportiche et al. (2014;2013, p. 24)
- The definition of c-command given here is taken from Haegeman (1994:147). The same or similar definitions of c-command can be found in numerous textbooks on syntax, e.g. Radford (2004:75) and Carnie (2013:127).
- Definition of immediate dominance is taken from Sportiche et al. (2014;2013, p. 120)
- Definition of c-command is taken from Reinhart (1981, p. 612)
- Carnie (2002:57) mentions this point, i.e. that Reinhart thanked Clements for suggesting the term c-command. The term c-command may also have been chosen so as to contrast with the similar notion kommand (often read as "k-command"), proposed by Lasnik (1976). See Keshet (2004) in this regard.
- See for instance Bruening's article in Language (2014). This article challenges the validity of c-command on more than one front.
- HPSG addresses the c-command effects in terms of o-command (obliqueness command). The syntactic functions are ranked in terms of their level of "obliqueness", subjects being the least oblique of all the functions. See Pollard and Sag (1994:248) and Levine and Hukari (2006:278f.).
- LFG addresses the c-command effects in terms of a straightforward ranking of syntactic functions associated with f-structure (functional structure). See Bresnan (2001:198).
- Concerning DGs emphasis on the importance of syntactic functions, see for instance Mel'c̆uk (1988:22, 69).
- Barker, C. (2012). Quantificational Binding Does Not Require C-command. Linguistic Inquiry, (pp. 614-633). MIT Press.
- Boeckx, C. (1999). Conflicting C‐command requirements. Studia Linguistica, 53(3), 227–250.
- Bresnan, J. (2001). Lexical functional syntax. Blackwell.
- Bruening, B. (2014). Precede-and-command revisited. Language, 90(1), 342–388.
- Carnie, A. (2002). Syntax: A generative introduction. Oxford: Blackwell.
- Carnie, A. (2013). Syntax: A generative introduction, 3rd edition. Malden, Mass.: Blackwell.
- Cho, K. (2019). Two Different C-commands in Intra-Argument Structures and Inter-Argument Structures: Focus on Binding Principles B and A. British American Studies (pp. 79-100). Hankuk University of Foreign Studies.
- Chomsky, N. (1995). "The Minimalist Program". MIT Press.
- Frawley, W. (2003). C-command. "International Encyclopedia of Linguistics".
- Haegeman, L. (1994). Introduction to Government and Binding Theory, 2nd edition. Oxford: Blackwell.
- Kayne, R. (1994). The antisymmetry of syntax. Linguistic Inquiry Monograph Twenty-Five. MIT Press.
- Keshet, E. (2004-05-20). "24.952 Syntax Squib". MIT.
- Klima, E. S. (1964). Negation in English. In J. A. Fodor and J. J. Katz (eds.), The structure of language: Readings in the philosophy of Language (pp. 246– 323). Englewood Cliffs, N.J.: Prentice-Hall.
- Langacker, R. W. (1969). On pronominalization and the chain of command. In D. A. Reibel and S. A. Schane (eds), Modern studies in English: Readings in transformational grammar(pp. 160–186). Englewood Cliffs, N.J.: Prentice-Hall.
- Lasnik, H. (1976). Remarks on coreference. Linguistic Analysis 2, 1-22.
- Levine, R. and Hukari, T. (2006). The unity of unbounded dependency constructions. Stanford, Calif.: CSLI Publications.
- Pollard, C. and Sag, I. (1994). Head-driven phrase structure grammar. Chicago: University of Chicago Press.
- Radford, A. (2004). English syntax: An introduction. Cambridge, UK: Cambridge University Press.
- Reinhart, T. (1976). The syntactic domain of anaphora. Doctoral dissertation, Massachusetts Institute of Technology. (Available online at http://dspace.mit.edu/handle/1721.1/16400).
- Reinhart, T. (1981). Definite NP anaphora and C-command domains. Linguistic Inquiry, 12(4), 605–635.
- Reinhart, T. (1983). Anaphora and semantic interpretation. London: Croom Helm.
- Reuland, E. (2007). Binding Theory. In M. Everaert and H. van Riemsdijk (eds.), The Blackwell companion to syntax, ch.9. Oxford: Blackwell.
- Sportiche, D., Koopman, H. J., and Stabler, E. P. (2013; 2014). An introduction to syntactic analysis and theory. Hoboken: John Wiley.
- c-command and pronouns
- Node relations, University of Pennsylvania
- Some Basic Concepts in Government and Binding Theory
- Isac, Daniela; Charles Reiss (2013). I-language: An Introduction to Linguistics as Cognitive Science, 2nd edition. Oxford University Press. ISBN 978-0-19-953420-3.