Center Embedding

A Center Embedding process embeds a Phrase in the middle of another Phrase of the same type.

• Context:
  • Is one of the Natural Language Parsing challenges.
  • Is addressed by Tree Adjoining Grammars.
• Example(s):
  • "The rat the cat chased ate the cheese” (a (Relative Clause).
  • "A man that a woman that a child that a bird saw knows loves.” (Relative Clause inside a relative clause).
  • Center Embedding of Complement Clauses in Dutch: Jan1 Piet2 Marie3 zag1 laten2 zwemmen3 (i.e. Jan saw Piet let Marie swim). It is possible to obtain a wide range of complex dependencies, i.e., complex combinations of nested and crossed dependencies. Such patterns arise in word order phenomena such as Scrambling and Clitic Movement and also due to Scope Ambiguity. (Joshi, 2007)
• See: Tree Adjoining Grammar, Relative Clause.

---

---

References

2017

• (Wikipedia, 2017) ⇒ https://en.wikipedia.org/wiki/Center_embedding Retrieved:2017-5-28.
  • In linguistics, center embedding is the process of embedding a phrase in the middle of another phrase of the same type. This often leads to difficulty with parsing which would be difficult to explain on grammatical grounds alone. The most frequently used example involves embedding a relative clause inside another one as in:

A man that a woman loves [math]\displaystyle{ \Rightarrow }[/math]

A man that a woman that a child knows loves [math]\displaystyle{ \Rightarrow }[/math]

A man that a woman that a child that a bird saw knows loves [math]\displaystyle{ \Rightarrow }[/math]

A man that a woman that a child that a bird that I heard saw knows loves

In theories of natural language parsing, the difficulty with multiple center embedding is thought to arise from limitations of the human short term memory. In order to process multiple center embeddings, we have to store many subjects in order to connect them to their predicates.

An interesting theoretical point is that sentences with multiple center embedding are grammatical, but unacceptable. Such examples are behind Noam Chomsky's comment that, "Languages are not 'designed for parsability' … we may say that languages, as such, are not usable." (Chomsky, 1991)

Some researchers (such as Peter Reich) came up with theories that though single center embedding is acceptable (as in "the man that boy kicked is a friend of mine"), double center embedding is not. The linguist Anne De Roeck and colleagues provided a counter-example: "Isn't it true that example-sentences that people that you know produce are more likely to be accepted?" (De Roeck et al., 1982).

2015

• (Troike, 2015) ⇒ Troike, R. C. (2015). Center-Embedding Relative Clauses in Coahuilteco 1. International Journal of American Linguistics, 81(1), 133-142. DOI:679045
  • Abstract: Coahuilteco, a long-extinct language of South Texas known primarily from a confessor’s manual (García 1760), had a basic SOV constituent order, with relative clauses occurring between the noun (NRel order) and a following demonstrative, a structure apparently typologically unique in North America (Troike 2010). As Kuno (1974) observed, the combination of SOV and NRel orders creates the potential for center-embedding of relative clauses within relative clauses, a circumstance realized in García’s text. Two levels of center-embedding are attested, as well as the use of extraposition possibly to avoid deeper embedding, supporting Kuno’s hypothesis that languages would utilize means to minimize the processing difficulties involved in comprehending multiply center-embedded structures.

2007

• (Joshi, 2007) ⇒ Aravind K. Joshi. (2007). “Complexity of Dependencies in Natural Language. Presentation, Vancouver, Feb 22.
  • Center Embedding of Complement Clauses in Dutch: Jan1 Piet2 Marie3 zag1 laten2 zwemmen3 (i.e. Jan saw Piet let Marie swim). It is possible to obtain a wide range of complex dependencies, i.e., complex combinations of nested and crossed dependencies. Such patterns arise in word order phenomena such as Scrambling and Clitic Movement and also due to Scope Ambiguity.

---