Chapter 4 – Linguistic environment & the Input hypothesis

Case Study

Lan is a 10-year-old student who has recently moved to a new city where English is used more often at school. At home, her family mainly speaks Vietnamese, but at school, her teachers encourage her to use English in class activities and group discussions. Lan understands many simple words and expressions, but she often feels shy when speaking. She learns new vocabulary from her classmates, teachers, books, and online videos, yet she notices that she learns faster when people speak directly with her and help her understand. Lan’s parents want to know how her linguistic environment, interaction with others, and exposure to English can support her language development.

1. What differences can you see between Lan’s language environment at home and at school?
2. Why might Lan learn English faster when people speak directly with her?
3. How do interaction and social context help Lan develop her language skills?
4. What challenges might Lan face as she learns English in a new environment?
5. What can Lan’s parents and teachers do to help her feel more confident and improve her English?

Introduction

Children begin communicating before they produce words. In the first year of life, they rely on crying, eye gaze, facial expressions, vocal play, and gestures to regulate interactions and signal needs. These early behaviors matter because they place infants in communicative exchanges that help them become attuned to speech, social intention, and patterns in the linguistic environment. Research on early language development shows that exposure to speech in the first year shapes neural and perceptual systems even before children begin speaking, making the linguistic environment central to language development from the outset (Kuhl, 2010; Saffran et al., 1996).

The importance of input has also been emphasized in second language acquisition. Krashen’s Input Hypothesis argues that acquisition develops when learners are exposed to comprehensible input that is slightly beyond their current level of competence. Although this hypothesis was developed for SLA rather than infant first language development, it remains influential because it foregrounds the role of meaningful exposure in acquisition. A useful distinction, therefore, is that early first language development depends on rich and socially embedded input, whereas the Input Hypothesis is a theory about how input supports development in additional language learning (Krashen, 1982; Kuhl, 2010).

First Language Acquisition

First language acquisition is the natural process through which children develop the sound system, vocabulary, grammar, and pragmatic use of the language or languages in their environment. This development does not occur through memorization alone. Instead, children appear to learn by combining exposure with powerful learning mechanisms that allow them to detect patterns, segment speech, and build form–meaning relationships over time. Saffran, Aslin, and Newport (1996), for example, showed that infants are sensitive to statistical regularities in speech, supporting the view that pattern detection plays an important role in early language learning (Saffran et al., 1996; Kuhl, 2010).

By the preschool years, most children have acquired the core structures of their first language, but development continues well beyond age five in areas such as narrative ability, academic language, figurative meaning, and discourse management. For this reason, first language acquisition is better understood as an extended developmental process rather than a task completed once children begin speaking fluently. The linguistic environment remains central throughout this process because children need sustained exposure to meaningful, responsive language use in order to refine and expand their competence (Kuhl, 2010).

Bilingual Acquisition

Bilingual acquisition refers to the development of two languages during childhood, often from birth or early in life. Research on early bilingualism shows that bilingual infants are capable of distinguishing their two languages and that the human capacity for language learning can support two linguistic systems from the beginning of development. Werker and Byers-Heinlein (2008) argue that bilingualism in infancy is not a sign of confusion but a normal developmental pathway shaped by experience with two languages (Werker & Byers-Heinlein, 2008).

At the same time, bilingual development does not simply duplicate monolingual development in each language. Hoff et al. (2012) found that bilingually developing children often show smaller vocabularies in each individual language than monolingual peers, while their total conceptual vocabulary across both languages may be comparable. This means that bilingual development must be interpreted in relation to the quantity and quality of exposure to each language, not by monolingual benchmarks alone (Hoff et al., 2012).

Bilingualism is also associated with broader communicative and cognitive consequences, although these should not be overstated. Grosjean (2010) argues that bilinguals are whole language users whose competence is distributed across languages according to context and need. Reviews by Bialystok, Craik, and Luk (2012) further suggest that bilingual experience can influence attentional control and cognitive processing, although the strength of these effects varies across populations and tasks (Grosjean, 2010; Bialystok et al., 2012).

Heritage Language Acquisition

Heritage language acquisition refers to the development or maintenance of a family or community language that differs from the dominant societal language. Heritage learners are highly diverse: some speak the heritage language fluently, while others mainly understand it or have uneven abilities across speaking, listening, reading, and writing. Because of this variability, heritage language development should not be treated as identical either to foreign language learning or to monolingual first language development (Valdés, 2005; Montrul, 2016).

A major concern in this area is language attrition or incomplete development, especially when opportunities to use the heritage language decline over time. Montrul (2016) shows that heritage speakers often retain strengths in pronunciation and informal oral language, while showing greater variability in morphosyntax, literacy, and formal registers. This means that heritage language acquisition is shaped not only by early exposure but also by continued use, schooling, and social value attached to the language (Montrul, 2016; Valdés, 2005).

Third Language Acquisition and Multilingualism

Third language acquisition refers to learning a language after at least two languages are already present in the learner’s repertoire. Multilingualism is therefore not simply an extension of bilingualism; it involves more complex patterns of interaction among languages, including transfer, competition, and facilitation across multiple systems. Cenoz (2013) emphasizes that multilingualism should be treated as a distinct phenomenon rather than as bilingualism plus one more language, because the relationships among languages can shape learning in unique ways (Cenoz, 2013).

Research on third language acquisition has paid particular attention to cross-linguistic influence, that is, the ways earlier-acquired languages affect the learning of a new one. Cenoz, Hufeisen, and Jessner (2001) argue that multilingual learners draw on more than one prior language, making transfer potentially more dynamic than in traditional L2 acquisition. This can create both advantages and difficulties, depending on linguistic similarity, proficiency, and learning context (Cenoz et al., 2001; Cenoz, 2013).

Multilingualism also has implications for how lexical systems are organized. Work on bilingual and multilingual word recognition suggests that lexical access is often nonselective, meaning that more than one language may be activated during processing. Dijkstra and van Heuven’s BIA+ model is influential in showing that multilingual lexical processing involves interaction across languages rather than strict separation, which helps explain why multilingual learners may experience both transfer and cross-language competition (Dijkstra & Van Heuven, 2002).

In brief the linguistic environment is fundamental to language development across first, second, heritage, and third language acquisition. In infancy, input supports perceptual tuning, pattern learning, and early communication; in SLA, comprehensible input remains a major theoretical construct; and in bilingual, heritage, and multilingual development, outcomes depend on how languages are distributed across home, school, and community contexts. A more accurate contemporary view is therefore that language acquisition is always shaped by experience, but that the form, timing, and social embedding of input differ across acquisition contexts (Kuhl, 2010; Krashen, 1982; Cenoz, 2013).

Linguistic Environment

The linguistic environment refers to the quantity, quality, and social distribution of the language that children or learners hear and use. Research consistently shows that language development depends not only on exposure in a general sense, but on meaningful, responsive, and developmentally appropriate input. Hoff (2003) showed that differences in early vocabulary growth were linked to differences in maternal speech, while Kuhl (2010) demonstrated that early exposure to speech shapes neural mechanisms for language processing. Together, these findings support the view that language learning is strongly influenced by the richness and responsiveness of the surrounding linguistic environment.

The linguistic environment is also crucial for vocabulary growth and processing efficiency. Weisleder and Fernald (2013) found that the amount of child-directed speech infants heard predicted both faster language processing and stronger vocabulary growth. This suggests that language input supports development not only by providing words and structures, but also by strengthening the child’s ability to process speech in real time. In other words, the environment influences both what children learn and how efficiently they learn it.

In bilingual settings, the linguistic environment matters in additional ways because children’s development in each language depends on how exposure is distributed across those languages. Hoff et al. (2012) showed that bilingual children’s rate of development in each language reflects the amount of input received in that language, and Place and Hoff (2011) further found that properties of dual-language exposure, including the number and type of speakers, influence bilingual proficiency in two-year-olds. A more accurate account of the linguistic environment, therefore, is that it includes not only input quantity but also input quality, speaker diversity, and the social contexts in which language is used.

Cognitive-Interactionism

A cognitive-interactionist view of language learning emphasizes that acquisition develops through the combined effects of input, interaction, attention, and learner processing. Rather than treating language learning as the passive result of exposure, this perspective assumes that learners actively process linguistic input, notice features, test hypotheses, and develop their interlanguage through communicative exchange. Long (1983)’s interactionist work is foundational here because it argues that conversational negotiation helps make input comprehensible and thereby facilitates learning.

Within this perspective, attention is essential. Schmidt (1990)’s Noticing Hypothesis argues that learners do not acquire linguistic features simply because those features are present in the input; rather, they must notice relevant aspects of the input for those aspects to become intake. This does not mean that all learning must be fully explicit, but it does mean that conscious attention to form plays an important role in language development.

Cognitive-interactionist accounts also stress that output matters alongside input. Swain (1985) argued that producing language pushes learners to test what they know, recognize gaps in their competence, and process language more deeply than comprehension alone may require. In this sense, interaction is valuable not only because learners receive input, but also because they are prompted to produce language, negotiate meaning, and refine what they say.

Krashen’s Input Hypothesis remains relevant to this discussion because it highlights the importance of comprehensible input in acquisition. However, later work in the interactionist tradition broadened the picture by showing that input becomes especially useful when learners engage with it through communication, feedback, and attention. A balanced summary, therefore, is that cognitive-interactionism views language learning as emerging from the interaction of comprehensible input, learner noticing, communicative output, and negotiation during interaction.

Acculturation Model

The Acculturation Model proposes that second language development is shaped not only by cognitive processing but also by the learner’s social and psychological relationship to the target-language community. In its original formulation, Schumann (1978) argued that learners acquire the target language to the extent that they acculturate to the target group. This model treats social distance, psychological distance, and degree of integration as central explanatory factors in L2 success or limitation.

One important strength of the model is that it explains why learners in apparently similar instructional conditions may achieve very different outcomes. Learners who have more meaningful contact with target-language speakers, more positive attitudes, and fewer social barriers are expected to have richer opportunities for input and use. Schumann’s (1986) later review of the model maintained that acculturation offers a useful framework for understanding success and failure in naturalistic SLA, even though it is difficult to operationalize all of its variables with precision.

At the same time, the model has also been criticized for being too broad as a predictor of L2 attainment. Block (2003), for example, argued that socially oriented explanations are important, but that no single social model fully captures the complexity of SLA. From this perspective, the Acculturation Model remains valuable as a sociolinguistic explanation of how social and affective conditions shape learning opportunities, but it should be treated as one part of a broader account rather than as a complete theory of L2 development.

Problem-Solving Task

Lan is learning English in a new school environment. She hears English from her teachers, classmates, books, and videos, but she still does not speak very much in class. She understands more when her teacher uses gestures, simple explanations, and examples. At home, her parents want to help, but they are not confident in English. After several months, Lan’s listening has improved, but her speaking is still weak, and she often feels nervous.

Your task:
Work in groups and solve this problem: How can Lan improve her English speaking in a supportive linguistic environment?

Discuss and decide:

1. What is the main reason Lan is not speaking confidently?
2. Which parts of her linguistic environment help her most?
3. How can her teacher modify classroom interaction to support her?
4. What kind of input does Lan need more of?
5. How can her parents help even if they are not strong in English?
6. What practical plan would you suggest for Lan for the next four weeks?

 

References

Bialystok, E., Craik, F. I. M., & Luk, G. (2012). Bilingualism: Consequences for mind and brain. Trends in Cognitive Sciences, 16(4), 240–250. https://doi.org/10.1016/j.tics.2012.03.001

Block, D. (2003). The social turn in second language acquisition. Edinburgh University Press.
URL: https://books.google.com/books/about/The_Social_Turn_in_Second_Language_Acqui.html?id=UTVsAAAAIAAJ

Cenoz, J. (2013). Defining multilingualism. Annual Review of Applied Linguistics, 33, 3–18. https://doi.org/10.1017/S026719051300007X

Cenoz, J., Hufeisen, B., & Jessner, U. (Eds.). (2001). Cross-linguistic influence in third language acquisition: Psycholinguistic perspectives. Multilingual Matters. https://books.google.com/books/about/Cross_linguistic_Influence_in_Third_Lang.html?id=E3VonNCY8TcC

Dijkstra, T., & Van Heuven, W. J. B. (2002). Modeling bilingual word recognition: Past, present and future. Bilingualism: Language and Cognition, 5(3), 175–197. https://doi.org/10.1017/S1366728902283017

Grosjean, F. (2010). Bilingual: Life and reality. Harvard University Press. https://doi.org/10.4159/9780674056459

Hoff, E., Core, C., Place, S., Rumiche, R., Señor, M., & Parra, M. (2012). Dual language exposure and early bilingual development. Journal of Child Language, 39(1), 1–27. https://doi.org/10.1017/S0305000910000759

Krashen, S. D. (1982). Principles and practice in second language acquisition. Pergamon Press. https://www.sdkrashen.com/content/books/principles_and_practice.pdf

Kuhl, P. K. (2010). Brain mechanisms in early language acquisition. Neuron, 67(5), 713–727. https://doi.org/10.1016/j.neuron.2010.08.038

Hoff, E. (2003). The specificity of environmental influence: Socioeconomic status affects early vocabulary development via maternal speech. Child Development, 74(5), 1368–1378.
DOI: https://doi.org/10.1111/1467-8624.00612

Hoff, E., Core, C., Place, S., Rumiche, R., Señor, M., & Parra, M. (2012). Dual language exposure and early bilingual development. Journal of Child Language, 39(1), 1–27.
DOI: https://doi.org/10.1017/S0305000910000759

Krashen, S. D. (1982). Principles and practice in second language acquisition. Pergamon Press.
URL: https://www.sdkrashen.com/content/books/principles_and_practice.pdf

Kuhl, P. K. (2010). Brain mechanisms in early language acquisition. Neuron, 67(5), 713–727.
DOI: https://doi.org/10.1016/j.neuron.2010.08.038

Long, M. H. (1983). Native speaker/non-native speaker conversation and the negotiation of comprehensible input. Applied Linguistics, 4(2), 126–141.
DOI: https://doi.org/10.1093/applin/4.2.126

Montrul, S. (2016). The acquisition of heritage languages. Cambridge University Press. https://www.cambridge.org/core/books/acquisition-of-heritage-languages/B1E3F13EE155199A86389DA89D3D4768

Place, S., & Hoff, E. (2011). Properties of dual language exposure that influence 2-year-olds’ bilingual proficiency. Child Development, 82(6), 1834–1849.
DOI: https://doi.org/10.1111/j.1467-8624.2011.01660.x

Saffran, J. R., Aslin, R. N., & Newport, E. L. (1996). Statistical learning by 8-month-old infants. Science, 274(5294), 1926–1928. https://doi.org/10.1126/science.274.5294.1926

Schmidt, R. W. (1990). The role of consciousness in second language learning. Applied Linguistics, 11(2), 129–158.
DOI: https://doi.org/10.1093/applin/11.2.129

Schumann, J. H. (1978). The acculturation model for second language acquisition. In R. C. Gingras (Ed.), Second language acquisition and foreign language teaching (pp. 27–50). Center for Applied Linguistics.
URL: https://books.google.com/books/about/Second_Language_Acquisition_Foreign_Lang.html?id=uj9iAAAAMAAJ

Schumann, J. H. (1986). Research on the acculturation model for second language acquisition. Journal of Multilingual and Multicultural Development, 7(5), 379–392.
DOI: https://doi.org/10.1080/01434632.1986.9994254

Swain, M. (1985). Communicative competence: Some roles of comprehensible input and comprehensible output in its development. In S. Gass & C. Madden (Eds.), Input in second language acquisition (pp. 235–253). Newbury House.
URL: https://www.semanticscholar.org/paper/Communicative-competence-%3A-Some-roles-of-input-and-Swain/fb4d094b6a03f2ae90e007d4117bd62224702317

Valdés, G. (2005). Bilingualism, heritage language learners, and SLA research: Opportunities lost or seized? The Modern Language Journal, 89(3), 410–426. https://doi.org/10.1111/j.1540-4781.2005.00314.x

Weisleder, A., & Fernald, A. (2013). Talking to children matters: Early language experience strengthens processing and builds vocabulary. Psychological Science, 24(11), 2143–2152.
DOI: https://doi.org/10.1177/0956797613488145

Werker, J. F., & Byers-Heinlein, K. (2008). Bilingualism in infancy: First steps in perception and comprehension. Trends in Cognitive Sciences, 12(4), 144–151. https://doi.org/10.1016/j.tics.2008.01.008

Case Study Lan is a 10-year-old student who has recently moved to a new city where English is used more often at school. At home, her family mainly speaks Vietnamese, but at school, her teachers encourage her to use English in class activities and group discussions. Lan understands many simple words and expressions, but she…