Summary: A new NYU study presents a multilingualism calculator that quantifies how multilingual a person truly is and identifies their dominant language. Instead of relying on vague labels such as “bilingual,” this tool combines the age at which each language was acquired with self-rated listening, speaking, reading, and writing proficiency to produce both a multilingualism score and a language-dominance profile.
Validated with both young adults and older adults with language impairments, the calculator matches the accuracy of more complex assessment methods while remaining simpler and faster to use. The approach offers researchers, educators, and clinicians a practical, evidence-based way to describe language backgrounds and compare multilingual abilities across individuals.
Key Facts
- New measurement tool: A calculator that integrates age of acquisition and self-rated proficiency across four language modalities.
- Validated accuracy: Produces dominance profiles consistent with more involved, traditional methods.
- Language dominance profile: Quantifies which language is strongest by comparing proficiencies across languages.
- Broad language coverage: Supports nearly 50 languages, including American Sign Language, and accepts custom language entries.
Source: NYU
More than half the global population speaks more than one language, yet there is no consistent, standardized way to define “bilingual” or “multilingual.” That ambiguity makes it difficult to measure proficiency reliably and to describe language histories in research, education, and clinical settings.
Researchers at New York University developed a multilingualism calculator that produces a clear numeric score representing where a person falls on a spectrum from monolingual to proficient multilingual. The calculator also identifies language dominance by computing comparative strengths between languages.
The formulas behind the tool are reported in the journal Bilingualism: Language and Cognition. Esti Blanco-Elorrieta, assistant professor of psychology and neural science at NYU and senior author of the paper, emphasizes that “multilingualism is a very broad label.” The new formulas provide a standardized, evidence-based way to understand language strengths and multilingual status.
Lead author Xuanyi Jessica Chen, an NYU doctoral student, and Blanco-Elorrieta designed the calculator to rely on two main inputs for each language a person knows:
- Age of acquisition for listening, reading, speaking, and writing
- Self-rated proficiency for listening, reading, speaking, and writing
From these inputs the calculator computes a multilingualism score, which places an individual on a continuum from monolingual to near-native ability in multiple languages. Separately, it calculates a dominance index to show which language is strongest based on differences in proficiency across languages.
The authors point out that self-rated proficiency is a practical and reliable indicator of actual ability when appropriate controls are applied; prior research supports its use. Age of acquisition is also an established predictor of language outcomes, with earlier exposure often associated with higher likelihood of native-like mastery.
To validate the tool, the team tested it in two populations: healthy young bilinguals and older bilingual adults with language impairments. They compared the results to existing methods that require much more detailed background information. Across both datasets, the calculator’s dominance profiles closely matched those produced by more complicated statistical approaches, demonstrating both efficiency and validity.
“Rather than simply labeling someone ‘bilingual’ or ‘monolingual,’ this calculator quantifies how multilingual a person really is,” says Chen. Blanco-Elorrieta adds that the transparent, quantitative output can help improve research design, inform educational practice, and support clinical assessment.
Funding: Supported by grants from the National Institutes of Health (R00DC019973) and the National Science Foundation (2446452).
Key Questions Answered:
A: People learn languages at different ages and vary widely across listening, speaking, reading, and writing abilities, so simple labels fail to capture meaningful differences in proficiency and dominance.
A: It quantifies multilingualism using age of acquisition and self-rated skills in listening, speaking, reading, and writing for each language a person knows.
A: Validation shows the calculator generates language-dominance results comparable to traditional, more time-consuming assessments while using a simpler, theory-driven formula.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- The journal paper was reviewed in full.
- Additional context was added by editorial staff.
About this neurotech and multilingualism research news
Author: James Devitt
Source: NYU
Contact: James Devitt – NYU
Image: The image is credited to Neuroscience News
Original Research: Open access. “A theoretically driven and empirically grounded calculation for language dominance and degree of multilingualism” by Esti Blanco-Elorrieta et al., published in Bilingualism: Language and Cognition.
Abstract
A theoretically driven and empirically grounded calculation for language dominance and degree of multilingualism
Bilingualism research has faced a persistent problem: the field lacks a unified, standardized way to quantify language dominance and the degree of multilingualism. Multiple language-history questionnaires collect useful background variables, but they do not provide a consistent formula to compute core measures from those data.
This study introduces two formulas that synthesize key linguistic variables—age of acquisition and self-rated proficiency across modalities—to efficiently calculate both language dominance and a multilingualism score spanning from strict monolingualism to native-like multilingualism. Validation across two large datasets shows the dominance measure closely aligns with principal-component-based methods while being simpler and more efficient to implement.