À quoi s’attendre en termes de développement du langage chez l’enfant bilingue?

What can be expected in terms of language development in a bilingual child?

December 17, 2025

Following my training in intervention with bilingual children, it is clear that determining whether a bilingual child is following their normal developmental trajectory is a key challenge for speech-language pathologists. Therefore, here are the stages of language development in bilingual children as documented in the literature.

Here, I distinguish between simultaneous bilingualism and sequential bilingualism. For a reminder of the definitions, you can read... My previous post is here .

So what are the stages of linguistic development in bilingual children?

LANGUAGE DEVELOPMENT OF SIMULTANEOUS BILINGUALS:

The major developmental milestones from 0 to 3 years are acquired at the same time in simultaneous bilinguals as in monolinguals.

A simultaneous bilingual who typically develops linguistically will use the grammatical structures expected at various developmental stages in each language. De Houwer (2009, p. 37) found that the following stages in simultaneous bilinguals appear at the same ages as in monolinguals:

Babbling, which appears between 6 and 9 months;
The emergence of the first words, which takes place between 10 and 12 months;
The emergence of the first 50 words (between 18 and 24 months),
The rate of vocabulary growth when considering vocabulary in both languages;
The first word combinations that appear between 18 and 24 months.

In addition, the average utterance length (AIL) is a good early indicator of grammatical development between 2 and 3 years old.

LANGUAGE DEVELOPMENT OF SEQUENTIAL BILINGUALS

In sequential bilingualism, the first three years (more or less) take place in a monolingual context, and subsequently when the second language is introduced. The following language stages are documented in the literature:

Stage 1 - House language: At this stage, the child who has just been introduced to the second language speaks and understands only their home language.

Stage 2 - Active silent period: The child is silent during this stage, but actively absorbs the new language. The child may or may not remain at this stage for a longer or shorter period. They do not speak, but may sometimes communicate with gestures.
This stage can last from a few weeks to a few months. It is a period of active listening where the child accumulates receptive vocabulary in the second language, but can often communicate with gestures.

Younger children may remain in this stage longer than older children. During this period, interaction with peers is a crucial factor for second language exposure and motivation to speak the language.

Why am I talking about motivation here? Because mutism (which is temporary, of course) can occur in sequential bilinguals and can cause guilt in the parent. During this stage, parents may question themselves, trying to understand why the child isn't communicating. This can put pressure on the child to communicate and break free from this mutism.

Note that this stage is not absolute, as each child is different. However, a child who develops typically will not remain at this stage; they will move on to the telegraphic production stage, stage 3.

Stage 3 - Stereotyped language: Here, the child will "copy and paste" short word combinations they have heard and memorized. Their productions will be telegraphic or imitative. For example: "Don't know" or "What's that?"

Stage 4 - Productive Language: At this stage, the child begins to produce sentences, but they are riddled with syntactic and grammatical errors. The sentences may seem what is called "ungrammatical," e.g., "Veux pas banane" rather than "Je ne veux pas la banane." When I talk about grammar here, I am referring to the linguistic structures specific to a language, not the rules learned in school. That is to say, a child who is simultaneously bilingual will not say "Je pas ai" because they say "I not have" in English. Just as with monolingual children, we will see simplified negations, for example, "J'ai pas," until the morphosyntax develops sufficiently for the child to say "I don't have a pencil" and "Je n'ai pas de crayon."

Stage 5 – Inter-language: The second language is now more or less mastered like the home language — L1 = L2. Mastering the second language in all its receptive and expressive aspects can take 5 to 7 years of complete immersion to reach the level of the first language. That being said, even towards the end of primary school, bilingual children will not yet have mastered all linguistic aspects to the same extent that a monolingual child has mastered their one and only language. They need to maintain the key elements: