Editing Language acquisition (section)

==Language diversity==
Kelly et al. (2015: 286) comment that “There is a dawning realization that the field of child language needs data from the broadest typological array of languages and language-learning environments.”<ref>{{cite journal |last1=Kelly |first1=B. |last2=Forshaw |first2=W. |last3=Nordlinger |first3=R. |last4=Wigglesworth |first4=G. |title=Linguistic diversity in first language acquisition research: Moving beyond the challenges |journal=First Language |date=2015 |volume=35 |issue=4–5 |pages=286–304|doi=10.1177/0142723715602350 |hdl=11343/217033 |hdl-access=free }}</ref> This realization is part of a broader recognition in [[psycholinguistics]] for the need to document diversity.<ref>{{cite journal |last1=Majid |first1=Asifa |title=Establishing psychological universals |journal=Nature Reviews Psychology |date=2023 |volume=2 |issue=4 |pages=199–200 |doi=10.1038/s44159-023-00169-w }}</ref><ref>{{cite journal |last1=Norcliffe |first1=Elisabeth |last2=Harris |first2=Alice C. |last3=Jaeger |first3=T. Florian |title=Cross-linguistic psycholinguistics and its critical role in theory development: early beginnings and recent advances |journal=Language, Cognition and Neuroscience |date=2015 |volume=30 |issue=9 |pages=1009–1032 |doi=10.1080/23273798.2015.1080373|hdl=11858/00-001M-0000-0028-7B21-7 |hdl-access=free }}</ref><ref>{{cite journal |last1=Singh |first1=L. |title=From information to action: A commentary on Kidd and Garcia |journal=First Language |date=2022|doi=10.1177/01427237221090024 |url=https://psyarxiv.com/s83yh/ }}</ref> Children's linguistic accomplishments are all the more impressive with recognition of the diversity that exists at every level of the language system.<ref>{{cite journal |last1=Evans |first1=Nicholas |last2=Levinson |first2=Stephen C. |title=The myth of language universals: Language diversity and its importance for cognitive science |journal=Behavioral and Brain Sciences |date=2009 |volume=32 |issue=5 |pages=429–492 |doi=10.1017/S0140525X0999094X|pmid=19857320 |hdl=11858/00-001M-0000-0012-C29E-4 |hdl-access=free }}</ref> Different levels of grammar interact in language-specific ways so that differences in morphosyntax build on differences in [[Prosody (linguistics)|prosody]], which in turn reflect differences in conversational style. The diversity of adult languages results in diverse child language phenomena that challenge every acquisition theory.

One such challenge is to explain how children acquire complex vowels in [[Oto-Manguean languages|Otomanguean]] and other languages. The complex vowels in these languages combine oral and laryngeal gestures produced with laryngeal constriction [ʔ] or laryngeal spreading [h]. The production of the [[Creaky voice|laryngealized]] vowels is complicated by the production of tonal contrasts, which rely upon contrasts in vocal fold vibration. Otomanguean languages manage the conflict between tone and laryngeal gesture by timing the gesture at the start, middle or end of the vowel, e.g. ʔV, VʔV and Vʔ. The phonetic realization of laryngealized vowels gives rise to the question of whether children acquire laryngealized vowels as single phonemes or sequences of phonemes. The unit analysis enlarges the vowel inventory but simplifies the syllable inventory, while the sequence analysis simplifies the vowel inventory but complicates the syllable inventory. The Otomanguean languages exhibit language-specific differences in the types and timing of the laryngeal gestures, and thus children must learn the specific laryngeal gestures that contribute to the phonological contrasts in the adult language.<ref>{{cite journal |last1=Silverman |first1=Daniel |title=Laryngeal complexity in Otomanguean vowels |journal=Phonology |date=1997 |volume=14 |issue=2 |pages=235–261 |doi=10.1017/S0952675797003412 }}</ref>

An acquisition challenge in morphosyntax is to explain how children acquire ergative grammatical structures. [[Ergative–absolutive alignment|Ergative]] languages treat the subject of intransitive verbs like the object of transitive verbs at the level of morphology, syntax or both. At the level of morphology, ergative languages assign an ergative marker to the subject of transitive verbs. The ergative marking may be realized by case markers on nouns or agreement markers on verbs.<ref>{{cite book |last1=Rumsey |first1=Alan |last2=San Roque |first2=Lila |last3=Schieffelin |first3=Bambi B. |date=2013 |editor-last1=Bavin |editor-first1=Edith L. |editor-last2=Stoll |editor-first2=Sabine |title=The Acquisition of Ergativity |publisher=John Benjamins |pages=133–182  |chapter=The acquisition of ergative marking in Kaluli, Ku Waru and Duna (Trans New Guinea) |isbn=9789027234797}}</ref><ref>{{cite book |last1=Brown |first1=Penelope |last2=Pfeiler |first2=Barbara |last3=de León |first3=Lourdes |last4=Pye |first4=Clifton |date=2013 |editor-last1=Bavin |editor-first1=Edith L. |editor-last2=Stoll |editor-first2=Sabine |title=The Acquisition of Ergativity |publisher=John Benjamins |pages=271–305 |chapter=The acquisition of agreement in four Mayan languages |isbn=9789027234797}}</ref> At the level of syntax, ergative languages have syntactic operations that treat the subject of transitive verbs differently from the subject of intransitive verbs. Languages with ergative syntax like [[K'iche' language|K'iche']] may restrict the use of subject questions for transitive verbs but not intransitive verbs. The acquisition challenge that ergativity creates is to explain how children acquire the language-specific manifestations of morphological and syntactic ergativity in the adult languages.<ref>{{cite journal |last1=Pye |first1=Clifton |title=The Acquisition of ergative languages |journal=Linguistics |date=1990 |volume=28 |issue=6 |pages=1291–1330 |doi=10.1515/ling.1990.28.6.1291 |hdl=1808/17433 |hdl-access=free }}</ref> The [[Mayan languages|Mayan]] language [[Mam language|Mam]] has ergative agreement making on its transitive verbs but extends the ergative marking to both the subject of intransitive verbs and the object of transitive verbs yielding transitive verbs with two ergative agreement markers.<ref>{{cite book |last1=Baugh |first1=John |title=Black Street Speech: Its History, Structure, and Survival |date=1983 |publisher=University of Texas Press |isbn=978-0-292-70743-6 }}{{page needed|date=December 2024}}</ref> The contexts for extended ergative marking differ in type and frequency between Mayan languages, but two-year-old children produce extended ergative marking equally proficiently despite vast differences in the frequency of extended ergative marking in the adult languages.<ref name="Pye Pfeiler acquisition of extended ergativity"/>

Children acquire language through exposure to a diverse variety of cultural practices.<ref>{{cite journal |last1=Pye |first1=Clifton |title=Towards an anthropology of language acquisition |journal=Language Sciences |date=1988 |volume=10 |pages=123–146|doi=10.1016/0388-0001(88)90009-5 }}</ref> Local groups vary in size and mobility depending on their means of subsistence. Some cultures require men to marry women who speak another language. Their children may be exposed to their mother's language for several years before moving in with their father and learning his language. Language groups have diverse beliefs about when children say their first words and what words they say. Such beliefs shape the time when parents perceive that children understand language. In many cultures, children hear more speech directed to others than to themselves, yet children acquire language in all cultures.

Documenting the diversity of child languages is made more urgent by the rapid loss of languages around the world.<ref>{{cite book |last1=Hale |first1=Kenneth |date=1998 |editor-last1=Grenoble |editor-first1=L. A. |editor-last2=Whaley |editor-first2=L. J. |title=Endangered Languages: Language Loss and Community Response |publisher=Cambridge University Press |pages=192–216 |chapter=On endangered languages and the importance of linguistic diversity}}</ref><ref>{{cite journal |last1=Krauss |first1=Michael E. |title=The world's languages in crisis |journal=Language |date=1992 |volume=68 |pages=4–10|doi=10.1353/lan.1992.0075 }}</ref><ref>{{cite book |doi=10.1017/CBO9781139106856 |title=Language Death |date=2000 |last1=Crystal |first1=David |isbn=978-0-521-65321-3 }}{{page needed|date=December 2024}}</ref> It may not be possible to document child language in half of the world's languages by the end of this century.<ref>{{cite journal |last1=Pye |first1=Clifton |title=Documenting the acquisition of indigenous languages |journal=Journal of Child Language |date=2021 |volume=48 |issue=3 |pages=454–479 |doi=10.1017/S0305000920000318 |pmid=32500845 }}</ref><ref>{{cite journal |last1=Kidd |first1=Evan |last2=Garcia |first2=Rowena |title=How diverse is child language acquisition research? |journal=First Language |date=2022 |volume=42 |issue=6 |pages=703–735 |doi=10.1177/01427237211066405 |doi-access=free }}</ref> Documenting child language should be a part of every [[language documentation]] project, and has an important role to play in [[Language revitalization|revitalizing]] local languages.<ref>{{cite book |last1=Eisenbeiss |first1=Sonja |date=2006 |editor-last1= Austin |editor-first1=P. K. |title=Language Documentation and Description |publisher=SOAS |pages=106–140|chapter=Documenting child language}}</ref><ref>{{cite journal |last1=Himmelmann |first1=N. P. |title=Documentary and descriptive linguistics |journal=Linguistics |date=1998 |volume=36 |pages=161–195 |doi=10.1515/ling.1998.36.1.161 }}</ref> Documenting child language preserves cultural modes of language transmission and can emphasize their significance throughout the language community.