Short answer: No. A 2025 longitudinal study published in the Journal of Child Language found bilingual children reach early speech milestones at the same age as monolingual children. The myth persists mostly because bilingual kids are sometimes measured in only one of their two languages.
Where does the speech delay myth come from?
It's an old worry: if a toddler is learning two languages at once, will one of them come later? Parents and even some clinicians have long assumed splitting attention between languages means slower progress in each. It's an understandable guess — and it's not what the data shows.
What does the new research say?
A study in the Journal of Child Language tracked 302 bilingual and 302 monolingual children from around 12 months old and found they reached early language milestones — first words, first combinations — at comparable ages. A separate longitudinal study following children from kindergarten through primary school found bilingual children actually outperformed monolingual peers on some language tasks in the early grades.
So why does it sometimes look like a delay?
The catch is measurement. A bilingual child's vocabulary in each individual language can look smaller than a monolingual peer's vocabulary in that one language — because words are split across two systems instead of stacked into one. Researchers now stress that what matters is combined vocabulary across both languages, not either language counted alone. A 2026 scoping review adds that bilingualism is also linked to stronger executive function — working memory, flexible thinking, self-control — alongside broader social and emotional benefits.
What should parents actually watch for?
- First words showing up around the typical range, in either language
- Steady growth in combined vocabulary across both languages over time
- Comfort switching between languages depending on who they're talking to
- Consistent exposure to both languages, rather than one dropped in favor of the other
If a child shows little to no language by around 18-24 months in either language, that's worth raising with a pediatrician — the same threshold that applies to monolingual children.
Does daily practice matter more than which method?
Consistency tends to matter more than any specific program. We've covered how much daily exposure actually moves the needle in our guide to bilingual practice time, and how a talking companion can add low-pressure daily practice in a second language, since Ted can hold real conversations in 60+ languages and adjusts to a child's level as they grow.
FAQ
Does bilingualism cause speech delay?
No. Current research shows bilingual children reach early speech milestones at the same age as monolingual children.
Why does my bilingual child seem to know fewer words than other kids?
They likely know just as many words overall — split across two languages. Combined vocabulary is the more accurate measure.
When should I actually be concerned about a bilingual child's speech?
If there's minimal language in either language by 18-24 months, talk to a pediatrician — the same guidance used for monolingual children.
Image brief: Warm pastel illustration of a young child sitting cross-legged with Ted the plush companion, speech bubbles in two different scripts/languages floating gently above them, soft home setting, no on-image text, 16:9 format. Alt text: "Child sitting with Ted, an interactive plush companion, with two gentle speech bubbles representing bilingual conversation."