Autonomous languages of twins.
Level 4 - case-series / case-control
Descriptive case series comparing linguistic features across nine twin languages.
PubMed 3434134 · doi:10.1017/s0001566000004463
What was done
The author analyzed and compared nine autonomous languages (cryptophasia or idioglossia) reported among twins and close siblings. The analysis evaluated the environmental circumstances surrounding their emergence, their relationship to the adult model language, and their structural and grammatical characteristics.
What was found
The author notes that autonomous languages appear in approximately 40% of twins but typically disappear quickly. Analysis of nine cases indicated that these languages typically emerge when close siblings lack adequate adult language modeling during language acquisition and use each other as models. Linguistically, the systems consisted of onomatopoeic expressions, few invented words, and predominantly adult words altered by early phonological constraints. They consistently lacked formal morphology and utilized word order driven by pragmatic principles, such as saliency and semantic scope, rather than syntactic rules.
Why it matters
This analysis clarifies that twin languages are not novel, independently invented linguistic systems, but rather situational, phonologically degraded adaptations of the surrounding adult language driven by peer modeling.
Limits
The study is limited to a small descriptive sample of nine languages with no control group or formal quantitative linguistic metrics presented in the abstract. The assertion of a 40% prevalence rate is stated without specific methodological or cohort details in the abstract.
Cited by
- supports Idioglossia (autonomous language) occurs in a percentage of twins prior to learning conventional language due to their continuous close proximity.