Evidence-based answer · Last updated · How it’s made
This question isn't really about French — it's a general one about language learning that happens to come from a French learner, so the honest answer is general: sign languages are full, complex human languages, and learning one as a second language works through the same basic acquisition processes as learning a second spoken language, with a few twists that come from using your hands and face instead of your voice. None of the sources here address French Sign Language and French learning specifically in a way that would let us say anything unique about "French learners and sign language" beyond one small French-focused study noted below.
Asked as someone learning French. Findings drawn from French-specific research are framed for French learners and may not hold for other languages; where the evidence is general second-language research, the report says so.
Across several studies, how early someone is first exposed to any first language predicts how well they can learn language later — and this holds whether that first language is spoken or signed. In other words, the 'sensory-motor modality' (whether a language is spoken or signed) doesn't change the basic age-related pattern.1,2,3
In plain terms
For hearing adults learning a sign language as a new second language, skills from their existing spoken language — vocabulary size and skill at telling sounds apart — predicted how much sign vocabulary and overall proficiency they gained, even though the two languages use completely different channels.4
Hearing non-signers learned new signs fastest and remembered them best the next day when a sign's shape visually resembled its meaning and also matched a natural gesture people would already make for that idea.5
Example
Adults learning a sign language as their second language go through recognizable second-language learning stages — they self-correct their errors less often as they get more fluent, they lean on fingerspelling more early on and less as their sign vocabulary grows, and they gradually build up more sophisticated storytelling and perspective-taking techniques.7,9,10,13,14
In plain terms
In observed sign language classrooms, teachers most often corrected students by simply repeating the sentence back correctly, and students frequently copied that correction — a pattern that looks different from typical feedback patterns reported in spoken-language classrooms.8
The one study here focused specifically on French Sign Language looked at brain responses in deaf signers and found that meaning-based grammar errors produced a recognizable brain response, similar to other sign and spoken languages, but grammar-structure errors did not show the expected brain signal, and age of first sign exposure did not clearly affect either type of processing in this data.12
A review of research on deaf youth's literacy, including studies of French deaf children who use French Sign Language, found that early and strong access to a sign language was linked with better reading and writing outcomes, and that skilled deaf readers tend to rely on visual word-recognition strategies rather than sounding words out.6
Now pick something to do it with
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