Editing Second-language acquisition (section)

=== {{anchor|Order of acquisition}} Sequences in the acquisition of English inflectional morphology ===
{{Main|Order of acquisition}}

In the 1970s, several studies investigated the order in which learners acquired different grammatical structures.<ref group="note">These studies were based on work by {{Harvtxt|Brown|1973}} on child first-language acquisition. The first such studies on child second-language acquisition were carried out by {{Harvs|txt|last=Dulay|last2=Burt|year=1973|year2=1974a|year3=1974b|year4=1975}}. {{Harvtxt|Bailey|Madden|Krashen|1974}} investigated the order of acquisition among adult second-language learners. See {{Harvtxt|Krashen|1977}} for a review of these studies.</ref>  These studies showed that there was little change in this order among learners with different first languages. Furthermore, it showed that the order was the same for adults and children and that it did not even change if the learner had language lessons. This supported the idea that there were factors other than language transfer involved in learning second languages and was a strong confirmation of the concept of interlanguage.
{| style="width: 30%; float: right; border: 1px solid #BBB; margin: 1em" cellspacing=3 padding=10
|-
| 1.
| Plural ''-s''
| ''Girls go''.
|-
| 2.
| Progressive ''-ing''
| ''Girls going''.
|-
| 3.
| Copula forms of ''be''
| ''Girls are here''.
|-
| 4.
| Auxiliary forms of ''be''
| ''Girls are going''.
|-
| 5.
| Definite and indefinite <br />articles ''the'' and ''a''
| ''The girls go''.
|-
| 6.
| Irregular past tense
| ''The girls went''.
|-
| 7.
| Third person ''-s''
| ''The girl goes''.
|-
| 8.
| Possessive '''s''
| ''The girl's book''.
|-
| colspan="3" | <small>A typical order of acquisition for English, according to Vivian Cook's 2008 book ''Second Language Learning and Language Teaching''.</small>{{sfn|Cook|2008|pp=26–27}}
|}However, the studies did not find that the orders were the same. Although there were remarkable similarities in the order in which all learners learned second-language grammar, there were still some differences between individuals and learners with different first languages. It is also difficult to tell when exactly a grammatical structure has been learned, as learners may use structures correctly in some situations but not in others. Thus it is more accurate to speak of ''sequences'' of acquisition, in which specific grammatical features in a language are acquired before or after certain others but the overall order of acquisition is less rigid.  

Recent studies have shown that universality and individuality coexist in the order of grammatical item acquisition.<ref>{{Cite journal |last1=Murakami |first1=Akira |last2=Alexopoulou |first2=Theodora |date=September 2016 |title=L1 INFLUENCE ON THE ACQUISITION ORDER OF ENGLISH GRAMMATICAL MORPHEMES: A Learner Corpus Study |url=https://www.cambridge.org/core/journals/studies-in-second-language-acquisition/article/l1-influence-on-the-acquisition-order-of-english-grammatical-morphemes/3263C3E82ECA4A7EB19D8F50E45FA1C3 |journal=Studies in Second Language Acquisition |language=en |volume=38 |issue=3 |pages=365–401 |doi=10.1017/S0272263115000352 |issn=0272-2631}}</ref> For example, items such as articles, tense, and the progressive aspect are particularly challenging for learners whose native languages, like Japanese and Korean, do not explicitly express these features. On the other hand, items like the third-person singular -s tend to be less influenced by the learner's native language. In contrast, articles and the progressive -ing have been confirmed to be strongly affected by the learners' native language. For more detailed information, please refer to the main articles on [[Order of acquisition]].