Editing Language acquisition (section)

=== Syntax, morphology, and generative grammar ===
As syntax began to be studied more closely in the early 20th century in relation to language learning, it became apparent to linguists, psychologists, and philosophers that knowing a language was not merely a matter of associating words with concepts, but that a critical aspect of language involves knowledge of how to put words together; sentences are usually needed in order to communicate successfully, not just isolated words.<ref name="Innateness and Language"/> A child will use short expressions such as ''Bye-bye Mummy'' or ''All-gone milk'', which actually are combinations of individual [[noun]]s and an [[operator (linguistics)|operator]],<ref>{{cite book|author= Fry, Dennis|year=1977|title=Homo loquens, Man as a talking animal|url= https://archive.org/details/homoloquensmanas00fryd|url-access= registration|publisher=Cambridge University Press|pages= [https://archive.org/details/homoloquensmanas00fryd/page/117 117]|isbn=978-0-521-29239-9}}</ref> before they begin to produce gradually more complex sentences. In the 1990s, within the [[principles and parameters]] framework, this hypothesis was extended into a maturation-based [[structure building model of child language]] regarding the acquisition of functional categories. In this model, children are seen as gradually building up more and more complex structures, with lexical categories (like noun and verb) being acquired before functional-syntactic categories (like determiner and complementizer).<ref>{{cite book|author= Radford, Andrew|year=1990|title=Syntactic Theory and the Acquisition of English Syntax|publisher=Blackwell|isbn=978-0-631-16358-9}}</ref>  It is also often found that in acquiring a language, the most frequently used verbs are [[irregular verbs]].{{Citation needed|date=September 2017}} In learning English, for example, young children first begin to learn the past tense of verbs individually. However, when they acquire a "rule", such as adding ''-ed'' to form the past tense, they begin to exhibit occasional overgeneralization errors (e.g. "runned", "hitted") alongside correct past tense forms. One influential{{citation needed|date=January 2020}} proposal regarding the origin of this type of error suggests that the adult state of grammar stores each irregular verb form in memory and also includes a "block" on the use of the regular rule for forming that type of verb. In the developing child's mind, retrieval of that "block" may fail, causing the child to erroneously apply the regular rule instead of retrieving the irregular.<ref>{{cite journal|vauthors=Marcus G, Pinker S, Ullman M, Hollander M, Rosen TJ, Xu F|year=1992|title=Overregularization in language acquisition|journal=Monographs of the Society for Research in Child Development|volume=57|issue=4|series=Serial No. 228|pmid=1518508|doi=10.1111/j.1540-5834.1992.tb00313.x|url=http://www.psych.nyu.edu/gary/marcusArticles/Marcus%20et%20al%201992%20SRCD%20Mono.pdf|pages=1–182}}</ref><ref>{{cite book|author1=Carlson, Neil  |author2=Heth, Donald|year=2007|title=Psychology the Science of Behaviour|publisher=Pearson Education:New Jersey}}</ref>