Child language disorders: language delay, autism and learning disability

In short

Child language disorders are impairments in understanding or using spoken, written or signed language that are not explained by hearing loss alone, and that limit a child's learning and participation. They span language delay and developmental language disorder (DLD), the social-communication disorder of autism spectrum disorder (ASD), and the reading, writing and arithmetic difficulties grouped as specific learning disability (SLD). For a BASLP student this is the single largest paediatric caseload in India: district early-intervention centres, DEIC under RBSK, DIC/CDC clinics, special schools and private practice. It is examined heavily in university theory and viva (normal milestones, differential diagnosis, Indian test batteries, management plans) and in interviews at AIISH, NIMH/NIEPID, AYJNISHD, DEICs and corporate hospitals. It is also a legal topic: ASD and SLD are both specified disabilities under the Rights of Persons with Disabilities Act, 2016, and SLPs must hold a valid RCI registration under the Rehabilitation Council of India Act, 1992.

Explained

Normal language development: the baseline for diagnosis

• Prelinguistic (0-12 months): reflexive vocalisation (0-2 m), cooing (2-4 m), babbling/reduplicated babbling (6-9 m), jargon and first word around 10-14 m. Joint attention, eye contact and proto-declarative pointing appear by 9-14 m - their absence is the earliest ASD red flag.
• Single word stage (12-18 months): 50-word expressive vocabulary by roughly 18 m; comprehension precedes production.
• Two-word stage (18-24 months): telegraphic speech, MLU rises; vocabulary spurt.
• 2-3 years: 200-1,000 words, simple sentences, 50-75% intelligible to strangers; follows two-step commands.
• 3-5 years: complex sentences, plurals, past tense, wh-questions, narratives, near-full intelligibility by 4 years.
• School age: metalinguistic skills, phonological awareness, reading decoding then comprehension, figurative language, discourse.
• Rule of thumb for Indian multilingual homes: total conceptual vocabulary across all languages, not one language, is the yardstick - bilingualism does not cause delay.

Language delay and developmental language disorder (DLD)

• Language delay: language emerging in the normal sequence but late for chronological age. Late talker = under 50 words and no word combinations at 24 months; roughly 13-20% of 2-year-olds, and a majority (about 50-70%) catch up ("late bloomers").
• Language disorder: the pattern is deviant, not merely slow, and persists - plateaus, scattered profile, poor response to stimulation.
• DLD (ICD-11 developmental language disorder; earlier SLI - specific language impairment): persistent language deficits with normal non-verbal cognition, normal hearing, no neurological/genetic syndrome; prevalence about 7% of school entrants. Language disorder associated with biomedical condition is the term used when it accompanies hearing loss, ID, ASD or a syndrome.
• Subtypes: expressive only; mixed receptive-expressive (poorer prognosis); predominantly phonological-syntactic; lexical-semantic; pragmatic.
• Causes/associations: hearing loss (including recurrent otitis media), intellectual disability, cerebral palsy, Down syndrome, Fragile X, Landau-Kleffner syndrome, prematurity/low birth weight, perinatal asphyxia, neglect and poor linguistic input, hypothyroidism, lead exposure, genetic loading (family history is strong).
• Differential diagnoses to rule out first: hearing impairment (always a PTA/BERA before labelling), intellectual disability, ASD, selective mutism, childhood apraxia of speech, maturational delay.

Autism spectrum disorder

• DSM-5-TR / ICD-11 definition: persistent deficits in (a) social communication and social interaction *plus* (b) restricted, repetitive patterns of behaviour, interests or activities - present in early development, causing functional impairment, not better explained by ID alone. DSM-5 merged the earlier autistic disorder, Asperger's and PDD-NOS into one spectrum.
• Domain A (all three required): social-emotional reciprocity; nonverbal communicative behaviours (eye contact, gesture, facial expression); developing and maintaining relationships.
• Domain B (two of four): stereotyped/repetitive motor movements, speech or object use (including echolalia, delayed echolalia, idiosyncratic phrases); insistence on sameness and rituals; highly restricted fixated interests; hyper- or hypo-reactivity to sensory input.
• Severity levels 1-3 ("requiring support", "requiring substantial support", "requiring very substantial support") graded separately for social communication and for RRBs; specifiers for accompanying ID, language impairment and known medical/genetic cause.
• Communication profile: pronoun reversal, failure of joint attention and protodeclarative pointing, literal comprehension, poor turn-taking and topic maintenance, prosodic oddities, hand-leading instead of requesting, loss of acquired words (regression) in about a quarter of cases, 25-30% remaining minimally verbal.
• Prevalence: about 1 in 100 children worldwide (WHO); Indian community studies (INCLEN, 2018) reported roughly 1 in 125 for 2-6 years and 1 in 85 for 6-9 years. Figures vary by method; treat any single number as an estimate.
• Indian tools: ISAA (Indian Scale for Assessment of Autism - 40 items, 6 domains, the instrument used for disability certification; score 70-106 mild, 107-153 moderate, above 153 severe, with 70+ taken as autism present), INDT-ASD (INCLEN Diagnostic Tool, DSM-based, validated in India), AIISH Autism Screening Tool, and the 3-item 3-COM / M-CHAT-R for screening. International: CARS-2, ADOS-2, ADI-R, GARS.
• Management is multidisciplinary: SLP targets joint attention, requesting, imitation, play and pragmatics using naturalistic developmental behavioural interventions (JASPER, ESDM, Milieu/Incidental teaching), ABA/DTT for discrete skills, PECS and AAC/speech-generating devices for minimally verbal children, TEACCH structured teaching, Social Stories and video modelling for older children, plus parent-mediated programmes (Project ImPACT, PACT) which carry the best evidence-to-cost ratio in Indian settings. Occupational therapy for sensory and motor issues; psychiatry for comorbid ADHD, anxiety, epilepsy, sleep problems.
• Not evidence-based: chelation, secretin, gluten-casein-free diets as a cure, facilitated communication, stem-cell therapy for autism - a frequent viva question.

Specific learning disability

• RPWD Act, 2016 definition: SLD is "a heterogeneous group of conditions wherein there is a deficit in processing language, spoken or written, that may manifest itself as a difficulty to comprehend, speak, read, write, spell, or to do mathematical calculations" and includes perceptual disabilities, dyslexia, dysgraphia, dyscalculia, dyspraxia and developmental aphasia.
• DSM-5-TR calls it specific learning disorder, with specifiers: *with impairment in reading* (dyslexia - word reading accuracy, rate, comprehension), *in written expression* (spelling, grammar, clarity), *in mathematics* (number sense, fact fluency, reasoning). Severity mild/moderate/severe.
• Criteria: persistent difficulty for at least 6 months despite targeted help; achievement well below age expectation (typically below the 7th-16th percentile, or -1.5 SD or more); onset in school years; not due to intellectual disability, uncorrected sensory loss, lack of schooling, psychosocial adversity or inadequate instruction in the language of teaching. Prevalence about 5-15% school age; Indian school surveys commonly report 5-15% depending on criteria.
• Language basis: phonological awareness (rhyme, syllable and phoneme segmentation/blending), rapid automatised naming, verbal working memory and morphosyntactic weakness. Many children with a preschool history of DLD later present as SLD - the "illusory recovery" pattern.
• Indian assessment tools: NIMHANS SLD Index/Battery (NIMHANS SLD Test), DTLD (Diagnostic Test of Learning Disability, Swarup & Mehta), GLAD (Grade Level Assessment Device for Children with Learning Problems in Schools, Jayanthi Narayan, NIMH/NIEPID), checklists from the Learning Disability Association of India (LDAI), BALD (Behavioural Assessment Scale), Dyslexia Assessment for Languages of India (DALI) - screening and assessment in Hindi, Marathi, Kannada etc., plus curriculum-based assessment and an IQ-achievement discrepancy only as supporting evidence.
• Intervention: multisensory structured language teaching (Orton-Gillingham style), explicit phonics and phonological-awareness training, morphological awareness, fluency building (repeated reading), reading-comprehension strategies, assistive technology (text-to-speech, screen readers), remedial education in the mother tongue plus English.
• Statutory concessions: certification (minimum 40% benchmark disability for most benefits) by a notified board; CBSE/ICSE/state boards and NTA permit extra time (usually 20 minutes per hour), a scribe/reader, calculator, exemption from a third language, question-paper reader, separate room and alternative questions in place of diagram/map work - the exact list is set by each board's current circular and changes, so verify against the latest notification.

Assessment: step-by-step clinical protocol

1. Case history: pregnancy, birth, milestones, medical and family history, languages at home and school, concern onset, previous therapy; parental concern is a strong predictor.
2. Rule out hearing loss: otoscopy, immittance, PTA/behavioural audiometry, OAE and ABR if needed. No language diagnosis without hearing status.
3. Screening/developmental scales: DDST-II, DASII (Developmental Assessment Scale for Indian Infants, Bharatraj), VSMS (Vineland Social Maturity Scale, Malin's Indian adaptation), LDS, M-CHAT-R, 3-COM.
4. Language tests, Indian norms: REELS (Receptive-Expressive Emergent Language Scale, 0-3 y), ALD (Assessment of Language Development, Lakkanna), 3-D LAT (Three-Dimensional Language Acquisition Test, Herlekar & Karanth, Kannada), LPT (Linguistic Profile Test, Karanth - phonology, semantics, syntax), CLIP (Computerised Linguistic Profile), MLT-K/H (Malayalam/Hindi Language Tests), RDLS (Reynell Developmental Language Scales), SECS, Kannada/Hindi Articulation Tests for the speech component.
5. Language sample: 50-100 utterances in play or conversation → MLU, TTR, syntax inventory, speech-act analysis.
6. Cognitive and functional measures: non-verbal IQ (Raven's CPM, Seguin Form Board, Bhatia's battery, MISIC/WISC-IV India), FACS/SFA or functional communication profiles, Vineland adaptive behaviour.
7. Diagnosis, severity, prognosis, and a written report with ICF-based goals; disability certification where applicable; counselling and referral.

Intervention principles and Indian service framework

• Choose targets by developmental sequence, functional usefulness to the family, and stimulability; write behavioural objectives (do-statement, condition, criterion e.g. 80% over 3 sessions).
• Approaches on a continuum: clinician-directed (drill, modelling, DTT) → hybrid (focused stimulation, vertical structuring, recast, milieu teaching) → child-centred (indirect language stimulation, self-talk, parallel talk, expansion, extension, It Takes Two to Talk/Hanen).
• Parent-mediated and home programme is the default in India given the SLP-to-population ratio; use the home language, train the caregiver, use routine-based activities (bathing, feeding, market).
• Early intervention law and schemes: RPWD Act, 2016 (21 specified disabilities including ASD, SLD, ID, speech and language disability; 4% reservation in government jobs, 5% in higher education, reasonable accommodation, 40% benchmark); National Trust Act, 1999 (Niramaya insurance, Disha, Vikaas, Gharaunda, legal guardianship for autism, CP, ID, multiple disability); RBSK under NHM with DEICs screening the 4Ds including developmental delay; Samagra Shiksha and the RTE Act, 2009 for inclusive schooling; NEP 2020 mandating screening for learning difficulties and the use of the mother tongue in early grades; UDID card for certification; RCI Act, 1992 - practising without RCI registration is punishable.
• Prognostic indicators: earlier intervention age, better receptive language and non-verbal IQ, functional play, joint attention, imitation, family involvement, absence of seizures, presence of some words by 5 years.
• Limitations to state honestly: Indian normative data are thin for several languages; most tests are normed on one or two languages and must be used descriptively in others; tele-practice extends reach but is weaker for play-based assessment.

Key points

• Language delay - late onset but normal sequence; language disorder - deviant pattern that persists and needs intervention.
• Late talker - fewer than 50 words/no word combinations at 24 months; many but not all catch up, so monitor rather than discharge.
• DLD (formerly SLI) - persistent language deficit with normal non-verbal IQ, hearing and neurology; about 7% prevalence.
• Red flags - no babbling by 9 m, no words by 16 m, no two-word phrases by 24 m, any loss of speech/social skills at any age → immediate referral.
• Hearing first - no child is labelled language-delayed before audiological evaluation.
• ASD dyad - social communication deficit plus restricted repetitive behaviour, early onset, with severity levels 1-3.
• Joint attention and protodeclarative pointing - the earliest and most discriminating ASD markers; hand-leading replaces requesting.
• Echolalia and pronoun reversal - classic ASD language features, not signs of intelligence or of mimicry alone.
• ISAA - the Indian instrument used for autism disability certification; ADOS-2 is the international gold-standard observation schedule.
• SLD - unexpected underachievement in reading, writing or maths, exclusionary criteria compulsory; dyslexia, dysgraphia, dyscalculia are its forms.
• Phonological awareness - the strongest preschool predictor of later reading, and the main remedial target in dyslexia.
• MLU - mean length of utterance in morphemes; the standard index of expressive syntax growth up to about 4 years.
• Indian test batteries - REELS, ALD, 3-D LAT, LPT, DASII, VSMS, NIMHANS SLD battery, DALI.
• Intervention continuum - clinician-directed, hybrid, child-centred; parent-mediated therapy is the Indian default.
• RPWD Act, 2016 - ASD and SLD are specified disabilities; 40% benchmark, 4% job reservation, 5% higher-education reservation, reasonable accommodation.
• National Trust Act, 1999 - schemes and legal guardianship for autism, CP, ID and multiple disabilities.
• RCI Act, 1992 - mandatory registration (CRR) for speech-language pathologists and audiologists in India.
• No evidence - chelation, secretin, special diets as cures, facilitated communication; do not offer or endorse them.

Formulas and examples

Example 1 - MLU, TTR and language quotient for a late talker. A 36-month-old boy from Pune, Marathi-speaking home. A 50-utterance play sample gives 110 morphemes, 92 words of which 40 are different words. REELS places receptive language at 30 months and expressive at 22 months.

• MLU (morphemes) = 110 ÷ 50 = 2.2 morphemes → Brown's Stage II, expected around 27-30 months, so syntax lags about 6-9 months.
• TTR = 40 ÷ 92 = 0.43 - slightly low, consistent with restricted vocabulary.
• Expressive LQ = (22 ÷ 36) × 100 = 61.1%; Receptive LQ = (30 ÷ 36) × 100 = 83.3%.
• Expressive percentage delay = [(36 − 22) ÷ 36] × 100 = 38.9%.
• Interpretation: mixed profile with expressive worse than receptive, more than 30% expressive delay → expressive language disorder; audiological evaluation plus a 2-3 session per week focused stimulation and parent-training programme in Marathi, review at 3 months.

Example 2 - ISAA scoring and certification. A 5-year-old scores 128 on the ISAA.

• 128 falls in 107-153 → moderate autism, which maps to the 50-74% disability band used for certification (mild 40-49%, severe 75-100%).
• As the score is above the 70 cut-off, autism is present; being above the 40% benchmark the child qualifies as a person with benchmark disability under the RPWD Act, 2016 - eligible for a UDID certificate, Niramaya insurance under the National Trust, and reasonable accommodation at school. (The exact percentage bands are fixed by the Ministry's gazette guidelines; quote the certificate, not a calculated figure.)

Example 3 - SLD identification in Class IV. A 9-year-old (CA 9;2) in an English-medium CBSE school in Chennai reads 32 words correctly in 2 minutes on a Grade-II passage, spells 6 of 20 words correctly, and scores non-verbal IQ 104 on Raven's CPM; hearing and vision are normal; she has had continuous schooling and 7 months of extra coaching.

• Reading rate = 32 ÷ 2 = 16 wcpm, against roughly 80-100 wcpm expected at Grade IV - a severe fluency deficit on material two grades below placement.
• Spelling accuracy = (6 ÷ 20) × 100 = 30%.
• Average non-verbal IQ, intact senses, adequate instruction, persistence beyond 6 months despite help → specific learning disorder with impairment in reading and written expression, moderate to severe.
• Action: phonological-awareness and multisensory phonics remediation, repeated-reading fluency work, text-to-speech, and application for certification plus board concessions (extra time, scribe, exemption from a third language as per the board's current circular).

Example 4 - therapy goal and progress measurement. Target: requesting with a two-word phrase. Baseline 3 of 20 opportunities. After 12 sessions the child produces 17 of 20.

• Baseline = (3 ÷ 20) × 100 = 15%; post-therapy = (17 ÷ 20) × 100 = 85%.
• Gain = 70 percentage points; the 80%-over-3-sessions criterion is met if it holds for two more sessions → move to three-word requests and generalisation to home and school.

Where it is used

• Government early intervention: DEICs under Rashtriya Bal Swasthya Karyakram, district disability rehabilitation centres (DDRC), composite regional centres and national institutes - AIISH Mysuru, AYJNISHD Mumbai, NIEPID Secunderabad, NIEPMD Chennai, SVNIRTAR, PGIMER, NIMHANS.
• Hospitals and clinics: paediatric and developmental-paediatrics departments, neuro-development clinics, child guidance centres, private SLP practice (typical urban therapy fee roughly ₹500-1,500 per session; government and NGO centres are free or subsidised).
• Schools: inclusive schools under Samagra Shiksha and the RTE Act, 2009; special educators and shadow teachers; remedial-education cells in CBSE/ICSE schools; board concession assessment and IEP writing.
• NGOs and parent bodies: Action for Autism (Delhi), Ummeed and Forum for Autism (Mumbai), Madhuram Narayanan Centre, Dyslexia Association of India, Maharashtra Dyslexia Association, Samadhan, Spastics Society units.
• Job roles: speech-language pathologist/ audiologist (RCI-registered), early interventionist, special educator (SLD/ASD), behaviour therapist/RBT, developmental therapist, tele-rehabilitation consultant, clinical supervisor and researcher; ASHA and anganwadi training in developmental screening.
• Products and industry: Indian-language AAC and therapy apps, speech-generating devices (ADIP scheme funds assistive devices), picture-exchange and visual-schedule kits, screening apps built on M-CHAT-R/3-COM, DALI screening packages for schools.

Interview questions

• Q: How do you distinguish language delay from language disorder? A: Delay follows the normal sequence but is late for age and often resolves with stimulation; disorder shows a deviant, scattered profile that persists and needs structured intervention.
• Q: What is the first investigation for any child brought with "no speech"? A: A full audiological evaluation - otoscopy, immittance, behavioural/pure-tone audiometry with OAE and ABR if needed - because undetected hearing loss is the commonest treatable cause.
• Q: Name the red flags that mandate immediate referral. A: No babbling by 9 months, no single word by 16 months, no two-word phrases by 24 months, no response to name, no pointing or joint attention by 12-14 months, and any regression of speech or social skills at any age.
• Q: State the DSM-5-TR criteria for ASD briefly. A: Persistent deficits in all three social-communication areas plus at least two of four restricted/repetitive behaviours, present in early development, causing impairment, not better explained by intellectual disability; severity graded 1-3 for each domain.
• Q: Which scale is used in India for autism disability certification and what are its bands? A: The Indian Scale for Assessment of Autism (ISAA) - 40 items in 6 domains; 70-106 mild, 107-153 moderate, above 153 severe, with 70 as the cut-off for presence of autism.
• Q: Does bilingualism cause or worsen language disorder? A: No. Bilingual children with DLD are no more impaired than monolingual ones; assess conceptual vocabulary across all languages, and intervene in the home language as well as the school language.
• Q: Will teaching a non-speaking autistic child to use PECS or an AAC device stop speech developing? A: No - evidence shows AAC and PECS do not inhibit speech and often increase vocalisation and requesting, because they reduce communicative frustration.
• Q: Which preschool skill best predicts later reading, and why? A: Phonological awareness, because decoding requires mapping phonemes onto graphemes; weak awareness is the core deficit in dyslexia and the main remedial target.
• Q: How does social (pragmatic) communication disorder differ from ASD? A: Both have social-communication deficits, but SPCD has no restricted or repetitive behaviours or sensory abnormalities; ASD must be ruled out first.
• Q: A 9-year-old with average IQ reads two grades below placement despite good teaching - your diagnosis and the statutory route? A: Specific learning disorder with impairment in reading; certify through a notified medical board using tools such as the NIMHANS SLD battery and apply for a UDID certificate and board examination concessions under the RPWD Act, 2016.
• Q: What legal registration must an SLP in India hold? A: Registration with the Rehabilitation Council of India under the RCI Act, 1992 (Central Rehabilitation Register); practising without it is an offence.
• Q: Which autism treatments would you refuse to recommend? A: Chelation, secretin, stem-cell therapy for autism, facilitated communication and gluten-casein-free diets as a cure - none has acceptable evidence and some carry real harm.
• Q: What are the good prognostic signs in a preschool child with ASD? A: Early intervention, better receptive language and non-verbal cognition, emerging joint attention and imitation, functional play, no seizures, and consistent family involvement.

Common mistakes

• Labelling a child language-delayed before hearing is tested, or attributing the delay to bilingualism, TV watching or "being the youngest child".
• Treating a late talker as inevitably destined to catch up and discharging without review - or, oppositely, over-diagnosing DLD at 24 months.
• Diagnosing ASD on repetitive behaviour or no-speech alone, without demonstrating deficits in all three social-communication areas.
• Using DSM-IV terms (Asperger's, PDD-NOS) or "mental retardation" in current reports, and quoting ICD-10 labels as if current.
• Applying tests normed in one Indian language to another and reporting standard scores from them rather than describing performance.
• Forgetting the exclusionary criteria for SLD (sensory loss, intellectual disability, inadequate instruction, adversity) and certifying on a discrepancy score alone.
• Computing MLU on too small a sample, counting words instead of morphemes, or including imitated and unintelligible utterances.
• Writing non-measurable therapy goals ("improve language") instead of condition-behaviour-criterion objectives, and omitting parent training and generalisation.

Related topics

Augmentative and alternative communication (AAC) · Articulation and phonological disorders · Hearing loss in children and aural rehabilitation · Language acquisition theories and multilingualism · Intellectual disability and cerebral palsy management · Disability legislation and the RPWD Act, 2016.