Cumulative Input Threshold Hypothesis in Third Language Acquisition: Morphosyntactic Transfer and Object Marking

The Cumulative Input Threshold Hypothesis

Introduction to Third Language Acquisition

Third language acquisition (L3A) research investigates how individuals learn a third language and the factors that influence transfer from previously acquired languages. The Cumulative Input Threshold Hypothesis posits that the amount and quality of input from prior languages determines the likelihood and extent of transfer to the L3, especially in morphosyntactic domains.

• Transfer: The process by which linguistic features from previously learned languages influence the acquisition of a new language.

• Non-facilitative transfer: Transfer that does not aid, and may hinder, acquisition of the target language.

• Facilitative transfer: Transfer that supports or accelerates acquisition.

Studies show that transfer can occur from both L1 and L2, but the degree of transfer is modulated by input thresholds and dominance relationships among the languages.

Key Variables in L3 Transfer

• Language Dominance: The relative proficiency and use of a language in an individual's repertoire. Dominance can affect which language is the primary source of transfer.

• Input Threshold: The minimum amount of exposure required for a language to serve as a source of transfer.

• Age and Context of Acquisition: Early and sustained exposure increases the likelihood of transfer.

Research (e.g., Puig-Mayenco, González Alonso, Rothman, 2019) suggests that transfer is more likely from the language with the highest cumulative input, regardless of whether it is the L1 or L2.

Morphosyntactic Domains in L3 Acquisition

Object Marking: Differential Object Marking (DOM)

Differential Object Marking (DOM) is a grammatical phenomenon in Spanish where animate, specific direct objects are marked with the preposition a. The presence or absence of DOM can signal different interpretations for animate objects.

• Animate and Specific: Marked with a (e.g., Juan busca a María – 'Juan is looking for María').

• Inanimate or Non-specific: Not marked (e.g., Rocco come la pizza – 'Rocco eats the pizza').

DOM is less frequent in Spanish for inanimate objects and is obligatory with animate, specific objects. Corpus studies show that about 27% of direct objects are marked in Spanish, with personal pronouns and animate objects being the most frequent.

Examples of DOM

• With DOM: Juan busca a María ('Juan is looking for María')

• Without DOM: Rocco come la pizza ('Rocco eats the pizza')

DOM is taught explicitly in Spanish classrooms, but its acquisition by L3 learners depends on input and transfer from previous languages.

Subject-to-Subject Raising Across a Dative Experiencer

This morphosyntactic structure involves the raising of a subject from an embedded clause to the matrix clause, often with a dative experiencer (REP). The configuration is sensitive to the features of the embedded subject and the matrix verb.

• Embedded TP: The embedded clause contains the subject and verb, which may be raised to the matrix clause.

• Dative Experiencer: The matrix clause contains a dative argument (e.g., Alicia me parece jugar muchos videojuegos – 'Alicia seems to me to play a lot of videogames').

Examples

• (5) Alicia me parece jugar muchos videojuegos ('Alicia seems to me to play a lot of videogames')

• (6) Alicia me parece que juega muchos videojuegos ('Alicia seems to me that she plays a lot of videogames')

• (7) Alicia parece jugar muchos videojuegos ('Alicia seems to play a lot of videogames')

Acceptability judgment studies show that L3 learners' performance on these structures is influenced by transfer from their previous languages and the amount of input received.

Empirical Findings and Applications

Transfer Patterns in L3 Learners

Studies comparing L3 learners with different language backgrounds (e.g., Spanish-dominant, Catalan-dominant, English-dominant) reveal that:

• Transfer is strongest from the language with the highest cumulative input.

• Non-facilitative transfer (errors or non-target-like structures) is more likely when input thresholds are not met.

• Facilitative transfer (target-like structures) increases with greater exposure and dominance.

Summary Table: Factors Affecting L3 Transfer

Factor	Description	Effect on Transfer
Language Dominance	Most frequently used and proficient language	Primary source of transfer
Input Threshold	Minimum exposure required	Enables transfer from that language
Age of Acquisition	Early vs. late learning	Early learning increases transfer likelihood
Classroom Instruction	Explicit teaching of structures	Facilitates acquisition and transfer

Conclusion

The Cumulative Input Threshold Hypothesis provides a framework for understanding how prior language experience shapes third language acquisition. Morphosyntactic domains such as Differential Object Marking and subject-to-subject raising are particularly sensitive to input thresholds and dominance relationships. For psychology students, these findings highlight the importance of exposure, proficiency, and instructional context in multilingual development.

Additional info: The notes expand on brief points in the original document, providing definitions, examples, and a summary table for clarity and completeness.