tl;dr-ELT

As someone living in a part of the world where bilingualism is common but often uneven  -only 9.4% of Catalans, for example, primarily use both Catalan & Spanish- I was intrigued by a recent study claiming that a mothers’ individual language use has twice the impact on a child’s bilingual exposure compared to a fathers’.

People often assume that the way families organise their language use -like using the classic OPOL, or “One-Parent-One-Language” strategy (whereby each parent consistently speaks a different language to the child)- is the key to raising balanced bilinguals. But what if we’ve been looking at the wrong level of detail?

A 2024 study by Sander-Montant, Bissonnette & Byers-Heinlein turns this assumption on its head. Drawing on data from 281 bilingual children in Montreal, the researchers found that a parent’s individual language use –not the family’s stated strategy– is what really shapes a child’s bilingual exposure.

The study

The researchers compared two predictors of bilingual language exposure:

• Family Language Strategies (FLS), like OPOL, both-parents-bilingual, or one-language-at-home
• Each parent’s actual language use, rated as “regularly”, “sometimes”, or “never” speaking each language with the child

Using the Language Exposure Questionnaire  -a validated tool aligned with the Multilingual Approach to Language Estimates (Byers-Heinlein et al., 2019)- they estimated each child’s lifetime exposure to their two languages. They also conducted longitudinal follow-ups with a subsample to track change over time.

Crucially, the children were split into two groups:

• Those acquiring two community languages (French & English)
• Those acquiring one community language + one heritage language (e.g., French & Arabic)

Key Findings

1. Individual parent language use predicted exposure far more accurately than FLS
   • FLS explained only ~6% of variance in language exposure
   • Parents’ individual use explained ~50%
   • This is a striking gap, considering how common FLS-based advice is in bilingual parenting literature & media
2. Mothers’ input was more influential than fathers’ across both groups
   • When mothers used a language regularly, it doubled or even tripled the child’s exposure compared to when fathers did
3. FLS categories may obscure real differences
   • OPOL assumes symmetry- but one parent may spend far more time with the child than the other -in Canada, for instance, 70% of mothers take parental leave vs. only 7% of fathers (StatsCan, 2023)
   • For example, two families labelled “one-parent-one-language” may differ drastically if, say, the father is the English-only speaker but rarely home before bedtime
   • Longitudinal data showed ~25% of families changed strategy over time  -often without realising it

These findings build on past research by Place & Hoff (2011) & Ferjan Ramírez et al. (2022), but this is the first large-scale study to directly compare FLS with parent-level input.

Why it Matters

While this study focuses on infants at home, the implications ripple outward. It suggests we may need to rethink how we frame bilingualism -not just as a family decision, but as something actively co-constructed through caregiver interaction over time.

What’s especially compelling is how it invites us to zoom in beyond tidy strategy labels like OPOL or “heritage-at-home”. These categories are often used in school intake forms or by language researchers -but they may not reflect the dynamic & asymmetric realities of everyday life.

This is especially important in heritage language contexts, where one parent may be the sole source of that language. If that parent uses it inconsistently -or simply has less time with the child- the language may not survive, regardless of the stated strategy.

In case you’re thinking it’s all down to the fact that mothers typically/traditionally spend more time with their children, caregiving time matters, but it’s only part of the picture. Mothers often choose to use certain languages more (especially the heritage language), and they tend to play a more active role in nurturing bilingualism, for a mix of practical & sociocultural reasons.

And for those who are concerned about mono-parental families, the study does acknowledge that caregiver time & language use -not the number of parents- is what matters most for bilingual exposure.

Teacher Takeaways?

While this study doesn’t directly impact classroom practice -it examines pre-school home exposure- it offers a fascinating window into how bilingual language development begins long before children reach your classroom.