When Should a Bilingual Child See a Speech-Language Therapist?

If a bilingual child has very limited vocabulary combined across both languages, weak non-verbal communication, or has lost skills they previously had — it's time for a professional evaluation, not for dropping one of the languages.

Quick answer

Seek an evaluation if: no words at all by 24 months (in any language); combined vocabulary in both languages is well behind what's expected for the child's age; non-verbal communication is weak (no pointing, imitation, or eye contact); you've noticed a regression; or a doctor or kindergarten has raised a concern. The right evaluation: covers both languages — not only Persian or only English. Avoid: dropping a language without a specialist's guidance.

What does the science say?

Clinical guidance for multilingual children emphasizes that a speech-disorder evaluation should be based on combined language capacity across all the child's languages — not vocabulary counted in a single language. An evaluation limited to one language can lead to a mistaken "delay" diagnosis, when in reality the child has simply split vocabulary between two languages. A speech-language therapist should assess both languages, or work with an interpreter or the parent. Dropping a language is not recommended as a default intervention. Bilingual children with sufficient exposure to both languages generally develop on a timeline similar to monolingual children — once the combined language total is properly accounted for.

• Assessment criterion: combined vocabulary and communication skills across all languages — not one language in isolation.
• A speech-disorder evaluation should be carried out in both languages.
• A monolingual-only evaluation can lead to a mistaken diagnosis in a bilingual child.
• Dropping a language is not the default solution — even after a disorder is diagnosed.
• With adequate exposure to both languages, bilingual children generally develop on a timeline similar to monolingual peers.

A practical guide for Iranian families

Checklist before your visit: ☐ Keep a 2–4 week word log: how many Persian words plus how many second-language words? ☐ Does the child communicate non-verbally? (pointing, imitating, eye contact) ☐ Have you noticed any regression in previous skills? ☐ Has a hearing test been done? During the visit: ☐ Ask for the evaluation to cover both languages ☐ Bring your word list for each language ☐ Ask: "Is dropping a language recommended?" (usually, no) ☐ In Iran: speech-therapy clinics, some university-affiliated hospitals, or a referral from a pediatrician At home until the appointment: continue both languages; keep Persian alive at dinner and in conversation; add 15–20 minutes of interaction or levelled cartoons (for example, on Lingome) for the second language.

Common mistakes

• Mistake: seeking help only because "English is weak," without counting the combined total; accepting advice to drop Persian; or expecting a monolingual-only evaluation from the therapist.
• Right approach: prepare a word list for each language, request a bilingual evaluation, continue both languages until a specialist advises otherwise, and get a hearing test.

When should we worry?

Signs worth following up on sooner rather than later: a clear regression in previous skills; not responding to their name by 12 months; not pointing by 18 months; no words at all by 24 months in any language; or complete avoidance of social interaction. This article is a general guide, not a diagnostic tool — every child is unique, and only an in-person evaluation can give the full picture.

If, after reading this, you're still worried about speech delay or your child's behaviour, a calm conversation with a doctor or speech-language therapist is a reasonable step — not necessarily a sign of something serious, but a way to gain peace of mind. This article is not a substitute for a specialist diagnosis.