Aims and objectives: What exactly happens to a mixed language’s system in a multilingual contact setting? This study aims to investigate the interactions between speakers’ exposure to, frequency of, and proficiency in four languages (English, Tagalog, Hokkien, and Mandarin) and their influences on the why-fronting only wh-question system of Lánnang-uè, a mixed language used by the metropolitan Manila Lannangs. It also aims to test the validity of the assertion that symbiotic mixed languages are more likely to be in flux.

Methodology: The Lánnang-uè speakers participated in production and acceptability experiments. Data analysis: Likelihood to front (production) and responses to a 7-point Likert-type scale (acceptability) were the dependent variables for several Bayesian linear mixed-effects models with age, frequency of language use, and language proficiency as primary fixed effects, sociolinguistic factors (e.g., attitudes, identity) as covariates, and participant (and when appropriate, item) as a random effect. Findings: Both production and acceptability results showed that the effects of contact are numerous and far from homogeneous. They vary depending on the source language, wh-phrase type, and degree of consciousness. They corroborate the widely held belief that mixed languages are more stable in symbiotic contexts. However, this paper goes an extra step to show that this “instability” or variability is not always a consequence of contact-induced transfer. It demonstrates that when the source languages influence the stability or development of the mixed language, the effects can be diverse, encompassing aspects such as identity processes, language attitudes, structural transfer, and/or other sociolinguistic innovations.

Originality: This article is one of the first studies to examine the effects of contact between multiple languages on a mixed language variable using both production and acceptability experimental data in a five-language context. It is one of the very few variationist works in the Philippines that considers the effects of multilingualism on variation and change.