Speech Recognition Datasets for ASR and Voice AI
Diverse, linguistically accurate speech corpora with phoneme-level transcriptions, speaker metadata, and accent coverage engineered for production ASR and voice AI systems.
20+
Years in AI training data
1,000+
Language locales
1M+
Hours of video annotated
ISO
27001 certified
The Challenge
Beyond Public ASR Benchmarks
LibriSpeech and Common Voice advanced ASR research. But production voice AI demands domain-specific vocabulary, accent diversity, and realistic acoustic conditions those benchmarks cannot provide.
Deployed voice assistants encounter regional accents, technical jargon, background noise, and spontaneous speech patterns absent from read-speech corpora. Models trained on public benchmarks degrade sharply in real environments.
Off-the-shelf ASR datasets suffer from read-speech bias (most speakers are reading aloud, not speaking naturally) and vocabulary gaps for specialized domains like healthcare, legal, or financial services.
LXT builds custom speech recognition datasets matched to your deployment environment, backed by a vetted supplier network with rights-cleared conversational speech across 100+ languages. We collect spontaneous, domain-specific, and environmentally realistic speech with human-verified transcriptions, speaker demographics, and noise profiles your model needs to generalize.
Why Teams Upgrade
Limitations of Public Speech Recognition Datasets
Standard benchmarks serve research well. Production deployments need more.
| Dataset | Primary Limitation | Impact |
|---|---|---|
| LibriSpeech | Read audiobook speech only; clean studio conditions; no domain-specific vocabulary or spontaneous speech | Read-speech bias |
| Common Voice | Crowd-sourced read sentences; uneven accent distribution; inconsistent audio quality across contributors | Quality variance |
| VoxPopuli | European Parliament speech only; formal register; limited vocabulary outside political/policy domain | Domain narrow |
| AISHELL-1 | Mandarin only; news-reading style; limited colloquial or regional dialect coverage | Geographic bias |
| FLEURS | Short evaluation sentences; no long-form conversational speech; limited domain coverage per language | Eval-only scale |
Not sure which specs you need?
Our data specialists help you scope the right dataset for your model architecture.
Configurable Specifications
Specs Built Around Your Model
Public datasets come fixed. Yours is configured for your architecture, environment, and use case.
Audio Quality
Recording Specifications
- Microphones: Close-talk, far-field, headset, and phone channel configurations
- Sample Rate: 16 kHz, 44.1 kHz, and 48 kHz depending on downstream pipeline
- Environments: Studio, office, vehicle, outdoor, and noisy public space conditions
Linguistic Coverage
Speech Diversity
- Accents: Regional and L2 accent coverage across target deployment geographies
- Register: Spontaneous conversation, command-style, dictation, and read speech
- Domain Vocabulary: Medical, legal, financial, technical, and custom terminology sets
Annotation Depth
Transcription Standards
- Verbatim: Word-for-word transcription including disfluencies, fillers, and restarts
- Phoneme Alignment: Forced-aligned phoneme boundaries for acoustic model training
- Speaker Tags: Speaker ID, gender, age group, native language, and accent region
Need a custom configuration?
We've built datasets across dozens of domains and use cases. Let's scope yours.
Capturing Complexity
Edge Cases in Speech Recognition
High-accuracy models handle rare attributes that public datasets miss.
Heavy Accent and Non-Native Speech
L2 speakers and strong regional accents produce phoneme substitutions that cause word error rate spikes. Targeted collection from underrepresented accent groups closes these gaps.
Overlapping and Cross-Talk Speech
Multi-speaker environments with simultaneous speech challenge diarization and recognition. Custom multi-channel recordings with known ground truth support separation model training.
Domain-Specific Terminology
Medical procedure names, legal citations, and technical product names absent from general corpora cause high OOV rates. Domain vocabulary seeding ensures coverage.
Degraded Channel Conditions
Phone compression codecs, VoIP artifacts, low-bandwidth recordings, and reverberant spaces create acoustic mismatch. Channel-matched collection prevents deployment degradation.
Ground Truth Quality
Human-in-the-Loop Annotation
Precise annotation bridges raw data and learnable signal. Expert annotators deliver precision automated tools can't match.
Verbatim Transcription
Expert transcribers produce word-for-word transcripts including disfluencies. Double-blind review and adjudication protocols ensure transcription accuracy above 98%.
Phoneme-Level Alignment
Forced alignment tools combined with manual correction produce time-stamped phoneme boundaries for acoustic model and pronunciation lexicon development.
Speaker Metadata Annotation
Each recording tagged with speaker ID, gender, age group, native language, dialect region, and recording environment for demographic balance verification.
Industry Applications
Speech Recognition Datasets for Your Domain
Custom taxonomies and collection protocols for specific deployment contexts.
Clinical Voice AI
Medical dictation, EHR voice entry, telehealth
Legal Transcription
Court reporting, deposition, contract review
Contact Center AI
Call routing, agent assist, quality monitoring
In-Vehicle Voice
Automotive voice control, navigation commands
Voice Assistants
Smart speaker, mobile assistant, IoT voice
EdTech
Language learning, pronunciation assessment
Broadcast Transcription
News captioning, podcast indexing, media search
Low-Resource Languages
Custom ASR for underserved language markets
Compliance & Ethics
Secure and Ethical Data Collection
Data collection involving people and sensitive content requires robust security, compliance, and ethical protocols at every stage.
Global Demographic Reach
Collection across 1,000+ locales and diverse demographics to prevent algorithmic bias in your deployed models.
ISO 27001 Certified
Sensitive projects processed in certified secure facilities meeting the highest information security standards.
GDPR & Privacy Compliance
All collection and annotation protocols vetted for consent and privacy. Legally robust for global deployment.
Frequently Asked Questions
Speech Recognition Dataset FAQs
What languages and accents can you cover?+
We cover 100+ languages and collect across regional accent variants within each language. For English, we target specific accent groups (Southern US, Indian English, West African English, etc.) with minimum speaker counts per variant.
How do you handle domain-specific vocabulary?+
We work with your terminology list to seed prompts and scenarios that elicit target vocabulary naturally. For highly specialized domains, we use subject matter experts as speakers.
What audio formats and sample rates do you deliver?+
WAV (PCM), FLAC, and MP3 at specified sample rates (16 kHz standard for ASR; 44.1 kHz for voice cloning). Transcripts in JSON, TextGrid, CTM, and custom formats.
Can you collect spontaneous conversational speech?+
Yes. We design task-based scenarios that elicit natural spontaneous speech rather than read sentences. This includes telephone conversations, task completion dialogues, and unscripted descriptions.
How do you ensure transcription accuracy?+
Each audio file is transcribed by a trained annotator, reviewed by a second annotator, and adjudicated where disagreements exist. We target greater than 98% word-level accuracy verified by internal QA sampling.
What does a custom speech recognition dataset cost?+
Most projects range from $15K for focused domain datasets (50-200 hours) to $150K+ for large multi-accent, multi-environment collections exceeding 1,000 hours.
Can you match our existing data distribution?+
Yes. Share a sample of your existing training data and we conduct a distribution analysis to identify gaps in accent, environment, register, or vocabulary before proposing a targeted collection plan.
Get Started
Scope Your Custom Speech Recognition Dataset
Share your target languages, accents, domain vocabulary, and deployment environment. An ASR data specialist will provide a detailed proposal within 48 hours.
Please provide us with the details of your inquiry and one of our team members will be in touch.
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Apply here to be considered for future projects including data collection, annotation and transcription
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