Sign language as harmful to deaf education
01
What institutions accepted
In 1880 the Milan congress of deaf educators treated speech as superior to signs and asserted that using speech and signs together injured speech, lip-reading and the “precision of ideas.” On that basis it preferred the oral method, and then pure oral instruction, over sign-based education.
02
What the evidence supports now
Natural sign languages are full, rule-governed human languages. With fluent input from birth, children acquire them on the same overall time scale as spoken languages; delayed access to any fully accessible first language risks language deprivation. A 2023 cross-sectional study of 56 deaf and hard-of-hearing children with hearing parents found ASL vocabulary positively associated with spoken-English vocabulary, a pattern inconsistent with inherent harm, but it could not establish causality. A 2016 systematic review found insufficient high-quality evidence to decide whether sign-plus-oral intervention produces better spoken-language outcomes than oral-only intervention. The evidence therefore rejects categorical exclusion of sign language without establishing one single best educational method for every child. Services should secure direct access to one or more fully accessible natural languages and respond to the individual child's needs.
03
Evidence for the overall belief
Open sources, locators and notes
- DocumentsHistorical beliefReport of the proceedings of the International Congress on the Education of the Deaf, Milan, 1880International Congress on the Education of the Deaf / Wellcome Collection
Where in the source: pp. 19–20 and 29–30
The official English report records the resolutions preferring speech to signs and claiming that simultaneous speech and signs injured speech, lip-reading and precision of ideas.
- SupportsPresent correctionAcquisition of Sign LanguagesAnnual Review of Linguistics
Where in the source: abstract
Reviews evidence that natural sign languages are acquired on the same time scale as spoken languages with fluent input from birth, and that delayed first-language access is associated with language and academic harms.
- SupportsPresent correctionLearning a Sign Language Does Not Hinder Acquisition of a Spoken LanguageJournal of Speech, Language, and Hearing Research / PubMed Central
Where in the source: abstract; Participants, Results, and Conclusions and Recommendations sections
In a cross-sectional sample of 56 ASL–English bilingual deaf and hard-of-hearing children aged 8–60 months with hearing parents, ASL and spoken-English vocabulary were positively associated. The authors explicitly state that the retrospective, correlational design cannot establish causality.
- SupportsPresent correctionAmerican Sign Language (ASL)American Speech-Language-Hearing Association
Where in the source: Position Statement and “Equivalence of Signed and Spoken Languages”
ASHA's official position identifies ASL as a distinct, rule-governed language with phonology, morphology, semantics, syntax and pragmatics, and summarizes linguistic, developmental and neurobiological equivalence.
- ContextualizesPresent correctionSign Language and Spoken Language for Children With Hearing Loss: A Systematic ReviewPediatrics / PubMed
Where in the source: abstract, Results and Conclusions
The review found eleven cohort studies and judged the high-quality comparative evidence insufficient to determine whether sign-plus-oral intervention is more effective for spoken-language outcomes than oral-only intervention.
- SupportsPresent correctionNatural Environments for Infants and Toddlers Who Are Deaf or Hard of Hearing and Their FamiliesAmerican Speech-Language-Hearing Association / Council on Education of the Deaf
Where in the source: “Defining Natural Environments” and “Making Decisions About Natural Environments”
Joint ASHA/Council on Education of the Deaf guidance calls for direct communication through one or more fully accessible natural languages and for planning around the individual child's language and communication needs.
- SupportsImpact1880 Milan Congress records — Memory of the WorldWorld Federation of the Deaf
Where in the source: “UNESCO Memory of the World of the 1880 Milan Congress,” opening paragraphs
Describes the resolutions as a marker of the long devaluation of sign languages and identifies the 2010 New Era statement as a rejection of the harmful Milan ideology.
- SupportsImpactKey documents for Deaf communities: the Milan Congress, 1880UNESCO Memory of the World
Where in the source: register description, paragraphs 1–3
UNESCO describes negative effects on access to language and education in many countries, exclusion of deaf teachers and widespread devaluation of signed languages, while characterizing Milan as a watershed rather than law.
- ContextualizesImpactLooking again at the International Congress of Education for the Deaf in Milan (1880): a historiographic challengeRevista Brasileira de História da Educação
Where in the source: paragraphs beginning “Very different from the usual narrative...” and “Final considerations”
The scholarly reappraisal rejects a simple story of a unanimous ban, total extinction of signing and passive Deaf communities, and situates Milan within earlier oralist organization and continued resistance.
04
Impact
At the Milan congress of 6–11 September 1880, the first resolution preferred speech to signs by about 160 votes to 4 and the second preferred the pure oral method by about 150 to 16. An eighth resolution recommended a staged conversion of schools: teach new pupils through speech, separate them from pupils completing their education with signs, and add a new speaking class each year. The congress did not legislate a worldwide ban. Oralism predated Milan, and signing and Deaf resistance continued after it. Its resolutions nevertheless gave oralism a powerful international professional reference point; UNESCO records negative effects on language and education in many countries, exclusion of deaf teachers and wider devaluation of signed languages. On 19 July 2010, the Vancouver congress's organizing committee and the British Columbia Deaf Community presented a statement rejecting the 1880 resolutions that denied sign languages a place in education.
Context
The Milan congress was an international professional meeting, not a legislature. Its resolutions did not enact a worldwide legal ban, and their adoption and enforcement differed among countries and schools.
Oralist organizing predated Milan. Recent historiography also cautions against making the congress the sole cause of a uniform 80-year disappearance of sign language: the votes were not unanimous, sign use continued and Deaf people resisted oralist policies.
The 1880 documents used terms such as “signs,” “simultaneous use” and “pure oral.” Natural sign languages, manually coded forms of spoken languages, home-sign systems and simultaneous communication are not linguistically interchangeable, so modern studies must be read according to what they actually measured.
The 2010 statement was a professional and symbolic reversal presented by the ICED Vancouver 2010 Organizing Committee with the British Columbia Deaf Community. It did not itself change national law, end oral-only practice everywhere or guarantee universal access to sign language.
Rejecting the inherent-harm claim does not make speech, hearing technology or oral instruction inherently harmful. Nor does it prove that one combined method has superior spoken-language outcomes for every child. The defensible requirement is timely access to language the child can fully perceive, with services responsive to the child's circumstances.
Recorded vote preferring speech to signs in the first 1880 resolution
Recorded vote preferring pure oralism to simultaneous speech and signs
Time from the Milan resolutions to the Vancouver statement rejecting their sign-excluding provisions
Historical totals and effects are presented as contextual evidence, not as universal causal claims.
Institutional episode 01
International — Milan 1880 and Vancouver 2010 congresses
Global
Milan's delegates endorsed speech over signs, characterized simultaneous speech and signs as harmful and recommended a gradual conversion of schools to pure oral instruction. The resolutions carried professional rather than legislative authority, but became an influential international reference within a broader oralist movement. In 2010, organizers of the Vancouver congress and the British Columbia Deaf Community rejected the provisions that had excluded sign languages and acknowledged their detrimental effects.
Institutions involved
- Second International Congress on the Education of the Deaf (Milan, 1880)
- ICED Vancouver 2010 Organizing Committee
- British Columbia Deaf Community
Institutional context
The international congress meeting in Milan from 6 to 11 September 1880 adopted a first resolution declaring speech superior to signs and a second saying simultaneous speech and signs injured speech, lip-reading and the precision of ideas. The official English report described the votes as about 160–4 and about 150–16. Its eighth resolution recommended gradual institutional conversion through speech-only entry classes, separation from older sign-taught pupils and one new speaking class each year. These were nonbinding professional resolutions, but they furnished an international reference point for an oralist movement already under way. On 19 July 2010, the Vancouver organizing committee and the British Columbia Deaf Community presented “A New Era: Deaf Participation and Collaboration,” rejecting the sign-excluding Milan resolutions, regretting their effects and calling for educational programs to respect all languages and forms of communication.
Why this persisted
EndorsementRecorded congress votes converted oralist claims into formal professional resolutions. The first two supplied the hierarchy and harm rationale; the eighth translated them into a staged school policy for replacing sign-taught cohorts with speech-only entry classes.
How correction happened
Corrected19 July 2010
Action: The ICED Vancouver 2010 Organizing Committee and British Columbia Deaf Community rejected the 1880 resolutions that denied inclusion of sign languages in deaf education.
Their “A New Era” statement acknowledged and sincerely regretted the Milan conference's detrimental effects and called on educational programs to accept and respect all languages and forms of communication. This was a formal reversal within the congress tradition, though it was not binding legislation.
Consequences
- International professional endorsement of oral instruction over sign-based education
- A proposed school-by-school phase-out of sign instruction through separate entry classes and annual expansion of speech teaching
- Use of the Milan resolutions as an institutional reference for oralist policy in multiple countries
- Reduced access to signed language in education and exclusion or marginalization of deaf teachers
- Wider devaluation of signed languages, while signing and Deaf resistance continued rather than disappearing uniformly
- A nonbinding 2010 professional reversal that acknowledged harm and endorsed linguistic and communicative plurality
Evidence for this episode
13 evidence linksOpen sources, locators and notes
- DocumentsInstitutional carrierReport of the proceedings of the International Congress on the Education of the Deaf, Milan, 1880International Congress on the Education of the Deaf / Wellcome Collection
Where in the source: title page; pp. 19–20, 29–30 and 40–41
Identifies the congress and preserves its adopted resolutions, approximate vote totals and institutional implementation proposal.
- DocumentsMechanismThe Milan Congress, 1880 — resolutionsDeaf History Europe
Where in the source: resolutions 1 and 2
Provides a readable transcription and vote cross-check for the two resolutions that ranked speech above signs and pure oralism above simultaneous speech and signs.
- DocumentsMechanismReport of the proceedings of the International Congress on the Education of the Deaf, Milan, 1880International Congress on the Education of the Deaf / Wellcome Collection
Where in the source: resolution 8, pp. 40–41
Documents the recommended gradual conversion: separate new speech-taught pupils from older sign-taught pupils and establish another speaking class each year until the latter completed school.
- SupportsConsequences1880 Milan Congress records — Memory of the WorldWorld Federation of the Deaf
Where in the source: “UNESCO Memory of the World of the 1880 Milan Congress,” opening paragraphs
Gives the World Federation of the Deaf's account of language deprivation and social marginalization associated with the legacy of the Milan resolutions.
- SupportsConsequencesKey documents for Deaf communities: the Milan Congress, 1880UNESCO Memory of the World
Where in the source: register description, paragraphs 1–3
Connects the resolutions to harms in many countries and specifically identifies exclusion of deaf teachers and devaluation of signed languages.
- ContextualizesContextLooking again at the International Congress of Education for the Deaf in Milan (1880): a historiographic challengeRevista Brasileira de História da Educação
Where in the source: sections “Paris (1878) and Lyon (1879)” and “Final considerations”
Shows that organized advocacy for oralism preceded Milan and cautions against treating the congress as a single, universally enforced cause of later deaf-education policy.
- DocumentsInstitutional correctionA New Era: Deaf Participation and CollaborationICED Vancouver 2010 Organizing Committee and British Columbia Deaf Community
Where in the source: Statement of Principle, p. 1; Accord for the Future, p. 2
The primary statement names its joint presenters, rejects the 1880 resolutions that denied inclusion of sign languages, regrets their effects and asks educational programs to respect all languages and communication forms.
- DocumentsInstitutional correctionRejection of ICED Milan decision embraced by deaf educators and leadersGallaudet University
Where in the source: paragraphs beginning “President Hurwitz...” through “The World Federation of the Deaf...”
Contemporaneously dates presentation of the statement to 19 July 2010 at the 21st ICED and records the response from Deaf educators and organizations.
- SupportsContextAcquisition of Sign LanguagesAnnual Review of Linguistics
Where in the source: abstract
Supplies the developmental evidence against treating a natural sign language as intrinsically inferior or linguistically harmful.
- ContextualizesContextLearning a Sign Language Does Not Hinder Acquisition of a Spoken LanguageJournal of Speech, Language, and Hearing Research / PubMed Central
Where in the source: abstract and Conclusions and Recommendations
Tests spoken-vocabulary harm directly while limiting the inference to an association in young ASL–English bilingual children rather than a universal causal treatment effect.
- SupportsContextAmerican Sign Language (ASL)American Speech-Language-Hearing Association
Where in the source: Position Statement
Establishes the modern professional recognition of ASL as a language with the same levels of organization found in other human languages.
- ContextualizesContextSign Language and Spoken Language for Children With Hearing Loss: A Systematic ReviewPediatrics / PubMed
Where in the source: abstract, Results and Conclusions
Prevents reversal into an overclaim: the available comparative intervention literature did not establish that one sign-plus-oral approach is superior to oral-only intervention for every spoken-language outcome.
- SupportsContextNatural Environments for Infants and Toddlers Who Are Deaf or Hard of Hearing and Their FamiliesAmerican Speech-Language-Hearing Association / Council on Education of the Deaf
Where in the source: “Defining Natural Environments,” paras. 1–4; “Making Decisions About Natural Environments,” paras. 1–4
Grounds the present-day alternative to a single imposed modality in accessible language, direct communication and individual educational planning.
Source registryEach source is registered once and can carry several precise evidence relationships.12 sources
- 01Report of the proceedings of the International Congress on the Education of the Deaf, Milan, 1880International Congress on the Education of the Deaf / Wellcome Collection3 evidence links
- 021 evidence link
- 031880 Milan Congress records — Memory of the WorldWorld Federation of the Deaf2 evidence links
- 041 evidence link
- 052 evidence links
- 06Learning a Sign Language Does Not Hinder Acquisition of a Spoken LanguageJournal of Speech, Language, and Hearing Research / PubMed Central2 evidence links
- 07Key documents for Deaf communities: the Milan Congress, 1880UNESCO Memory of the World2 evidence links
- 08Looking again at the International Congress of Education for the Deaf in Milan (1880): a historiographic challengeRevista Brasileira de História da Educação2 evidence links
- 09A New Era: Deaf Participation and CollaborationICED Vancouver 2010 Organizing Committee and British Columbia Deaf Community1 evidence link
- 102 evidence links
- 112 evidence links
- 12Natural Environments for Infants and Toddlers Who Are Deaf or Hard of Hearing and Their FamiliesAmerican Speech-Language-Hearing Association / Council on Education of the Deaf2 evidence links