ASL Vs BSL — Complete Comparison Guide

The debate around ASL vs BSL often starts with a simple question: why are they so different? American Sign Language and British Sign Language serve Deaf communities in two English-speaking nations, yet they are as distinct as French is from Japanese. This comprehensive comparison covers the origins, structure, and practical differences that make each language unique.

The French Connection: Why ASL Is Not British

The single most important fact about the ASL vs BSL comparison is that these languages belong to entirely different language families. ASL developed from French Sign Language (LSF) in the early 1800s, while BSL evolved independently within the British Deaf community over centuries. This makes ASL linguistically closer to French Sign Language than to the sign language of its closest English-speaking ally.

The story begins with Thomas Hopkins Gallaudet’s trip to Europe in 1816. Gallaudet wanted to learn Deaf education methods to bring back to America. His first stop was England, where the Braidwood family ran the most prominent Deaf schools. However, the Braidwoods considered their methods proprietary and refused to train Gallaudet. Discouraged but determined, he travelled to Paris, where he met Laurent Clerc at the Institut National de Jeunes Sourds.

Clerc, a Deaf man who had been educated in French Sign Language, agreed to accompany Gallaudet to America. Together they founded the American School for the Deaf in Hartford, Connecticut in 1817. Clerc taught using LSF, which gradually blended with the local sign languages already in use among American Deaf people — including the well-documented Martha’s Vineyard Sign Language — to produce modern ASL.

This historical accident means that ASL shares approximately 60 percent of its vocabulary with French Sign Language but only about 30 percent with BSL. To put this in perspective, BSL shares roughly 80 percent of its vocabulary with Australian Sign Language (Auslan), making a BSL signer far more likely to understand an Australian than an American Deaf person.

Key Structural Differences

The structural differences between ASL and BSL go beyond vocabulary. The most visible distinction is in fingerspelling: ASL uses a one-handed alphabet inherited from France, while BSL uses a two-handed alphabet native to Britain. These systems share no common letter formations, and knowledge of one provides no foundation for learning the other.

Mouth patterns represent another significant structural difference. In BSL, mouthing — the production of English word shapes on the lips while signing — serves an important grammatical function. It can distinguish between signs that have identical hand movements but different meanings, effectively acting as an additional phonological parameter. ASL uses mouthing as well, but it plays a less systematic grammatical role.

Both languages are spatial, using the area in front of the signer to establish references and show relationships. However, the specific conventions for spatial grammar — how locations are assigned, how verb agreement works, and how the signing space is organised — differ between the two languages. A grammatically correct ASL sentence might follow different spatial rules than a grammatically correct BSL sentence.

Non-manual markers (facial expressions, head movements, and body posture used for grammatical purposes) are essential in both languages but follow different rules. Both raise eyebrows for yes-or-no questions and furrow brows for wh-questions, but the exact execution, timing, and combination with manual signs vary. Learning the non-manual grammar of one language does not automatically transfer to the other.

Word order flexibility exists in both languages, but the default patterns and available variations differ. BSL tends toward topic-comment structure as a primary organisational strategy, while ASL employs topic-comment alongside other structures such as Subject-Verb-Object, depending on discourse context and emphasis needs.

Everyday Signs Side by Side

Examining specific signs reveals just how different ASL and BSL are in practice. Consider greetings: the ASL sign for “hello” resembles a military salute, while the BSL sign for hello uses a different hand position and movement entirely. These signs share no visual similarity whatsoever.

Family vocabulary is another area of stark contrast. The ASL sign for “mother” involves an open hand with the thumb touching the chin, while BSL uses a completely different formation. Signs for father, brother, sister, and other family members are all produced differently in each language, with no shared forms.

Colour signs highlight an interesting structural difference. Many BSL colour signs are produced near or on the lips and involve a mouth pattern, reflecting BSL’s integration of mouthing as a grammatical feature. ASL colour signs are typically produced in the neutral signing space with distinctive hand movements — wiggling, twisting, or tapping — and are not associated with specific mouth patterns.

Numbers show yet another divergence. Both languages start counting on one hand, but the starting finger and the way numbers progress differ. ASL starts with the index finger for “one” and progresses across the hand. BSL starts differently, and the two-handed nature of the alphabet carries over into some number formations for larger values.

Even signs that appear similar on the surface may have different meanings in each language. This phenomenon, called “false friends” in linguistics, can lead to amusing or embarrassing miscommunications. A hand configuration that means one thing in ASL might convey something entirely different — or nothing at all — in BSL. This further emphasises that ASL and BSL must be treated as separate languages requiring independent study.

Learning Resources for Each Language

Learning ASL and learning BSL are separate undertakings, each requiring dedicated resources and community engagement. For ASL learners, resources include Gallaudet University’s online materials, the ASL dictionary websites, community college classes, and local Deaf community events across the United States and Canada.

For BSL learners, the landscape includes courses offered by Deaf organisations such as the British Deaf Association, college and university programs, and online resources. In the UK, BSL qualifications are offered at Levels 1 through 6, with Level 3 being the standard for conversational fluency and Level 6 representing near-native competence.

Online dictionaries serve both communities. For BSL, Deafened.org provides dictionary entries for signs like love, happy, and hundreds of other common words. These resources supplement but cannot replace the immersive experience of learning from Deaf native signers in a community setting.

Regardless of which language you choose to study, the most effective learning strategy combines structured classes (preferably taught by Deaf instructors), regular engagement with the Deaf community, and consistent daily practice. Both ASL and BSL are complex, fully developed languages that reward dedicated study with the ability to connect with vibrant cultural communities.

Bridging the Gap Between ASL and BSL

While ASL and BSL are mutually unintelligible, the global Deaf community has developed strategies for cross-linguistic communication. International Sign (IS) is a contact variety used at events like the Deaflympics, World Federation of the Deaf congresses, and international Deaf gatherings. IS draws on elements of multiple sign languages, shared visual strategies, and gesture to facilitate understanding across language boundaries.

Technology is also playing a role in bridging the gap. Video relay services, online sign language learning platforms, and social media have made it easier for Deaf people from different countries to interact and develop familiarity with each other’s languages. Some Deaf content creators produce videos with captions or visual explanations that make their content accessible to signers of other languages.

For hearing learners who interact with both ASL and BSL communities — perhaps due to living in one country but having family or professional connections in the other — learning both languages is possible but requires treating each as an independent study. Skills from one do not directly transfer to the other, though the general understanding of visual-spatial grammar and Deaf culture that comes from studying any sign language provides a conceptual foundation.

The existence of two very different sign languages in English-speaking countries is a powerful reminder that sign languages are independent linguistic systems. They are not manual codes for spoken languages but living, evolving languages shaped by the Deaf communities that use them. Understanding the ASL vs BSL comparison deepens your appreciation for the remarkable diversity of human language in all its forms.

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