Oct 17, 2026 · 11 min read
Speech Data Collection Companies: Who Records Custom Datasets
Speech data collection companies compared: who records speech to order, how (remote, studio or on-site), which languages they claim, and what to ask.
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Speech data, explained properly
What we’ve learned collecting, transcribing, and licensing tens of thousands of hours of speech, written for the teams training the models.
Oct 17, 2026 · 9 min read
Spanish and Portuguese Speech Data: Which Variety Do You Need?
Spain or Mexico, Portugal or Brazil: how Spanish and Portuguese varieties differ for speech models, which to buy for each market and how to test them.
Oct 17, 2026 · 8 min read
Off-the-Shelf vs Custom Speech Data: How to Choose
When to license off-the-shelf speech data, when to commission custom collection, and how to combine both, with a decision table and worked costs.
Oct 17, 2026 · 10 min read
Arabic Speech Recognition: Dialects, Data and Spelling
Why Arabic ASR struggles with dialect speech, what the MGB challenges measured, how to spell dialect transcripts and which dialect data each market needs.
Oct 13, 2026 · 10 min read
Verbatim vs. Clean Verbatim Transcription: What Speech AI Needs
Verbatim, clean verbatim and intelligent verbatim transcription compared for ASR and TTS data, with a worked WER example and a guideline checklist.
Oct 13, 2026 · 9 min read
Switchboard Corpus, Fisher and CALLHOME: Commercial Alternatives
What the Switchboard corpus, Fisher and CALLHOME contain, how LDC licenses them, and two-channel conversational speech you can use commercially.
Oct 13, 2026 · 9 min read
Inter-Annotator Agreement in Speech Data: Kappa, Alpha and WER
How to measure inter-annotator agreement on speech data: Cohen's and Fleiss' kappa, Krippendorff's alpha, transcript WER and DER, with a worked example.
Oct 13, 2026 · 9 min read
Forced Alignment: How to Get Word Timestamps for Speech Data
How forced alignment turns a transcript into word and phone timestamps: MFA, WhisperX and MMS compared, why alignment fails, and what to specify.
Oct 13, 2026 · 9 min read
Dual-Channel Audio for Call Analytics and Voice AI
Dual-channel audio puts each speaker of a call on its own channel. What that enables for call analytics and voice AI, how to record it, and what to check.
Oct 13, 2026 · 10 min read
Deepfake Audio Detection Data: Why Real Speech Matters
Audio deepfake detection fails when the real speech in training doesn't match production. Public datasets, their licenses and a spec for the bona fide set.
Oct 13, 2026 · 7 min read
Appen Alternatives for Speech Data
Appen alternatives for ASR and TTS training data: what Defined.ai, LXT, Shaip, FutureBeeAI, Nexdata, DataForce, TELUS Digital and SpeechData.ai offer.
Oct 10, 2026 · 5 min read
Speech Data Providers Compared: How to Choose One in 2026
Speech and voice data providers compared: open datasets, commercial vendors such as Appen, Defined.ai, LXT and Shaip, and a checklist for choosing one.
Jul 18, 2026 · 7 min read
How to Choose an Audio Annotation Vendor
A buyer's guide to choosing an audio annotation vendor: how annotation is priced, how to judge quality, what to ask, and when to build in-house.
Jul 17, 2026 · 6 min read
The Data Behind Voice Cloning: Recordings, Consent, and Quality
Voice cloning training data: recording quality, speaker consent and licensing checks for teams evaluating data before building a voice model.
Jul 16, 2026 · 7 min read
Wake Word Detection: How It Works and How to Train a Custom Wake Word
Wake word detection explained: how always-on keyword spotting works, false accepts vs false rejects, tools like Porcupine and openWakeWord, and training data.
Jul 16, 2026 · 5 min read
Synthetic Speech Data vs Real Recordings: What Trains Better Models
When synthetic speech data helps, when it hurts, and how to combine it with real recordings. A practical comparison for teams training ASR and voice AI.
Jul 16, 2026 · 6 min read
Speech Data Collection: The Complete 2026 Guide
Speech data collection from spec to delivery: recruitment, consent and GDPR, recording setups, QA, transcription, costs, and the build-vs-buy decision.
Jul 16, 2026 · 6 min read
How to Fine-Tune Whisper: Data, Setup and Evaluation
Prepare a Whisper fine-tune: choose a baseline, check audio-text pairs, separate evaluation and configure checkpoint selection before scaling a run.
Jul 15, 2026 · 8 min read
Speech Data for Voice Agents and Call-Center AI
Speech data for voice agents: two-party phone audio, domain vocabulary and test sets, sourced from licensed datasets or role-played calls.
Jul 14, 2026 · 6 min read
Voice Data Privacy: Consent, PII, and GDPR for Speech Datasets
How to handle consent, personal data, and PII redaction in speech datasets. A practical compliance primer for teams collecting or buying voice data.
Jul 13, 2026 · 6 min read
Accent and Dialect Diversity in Speech Data
Plan accent and dialect coverage for ASR with an evaluation checklist, a hypothetical recording brief, and limits on what new data can fix.
Jul 9, 2026 · 7 min read
Word Error Rate (WER) Explained: How to Measure Speech Recognition Accuracy
Word error rate (WER) explained: the (S+D+I)/N formula with a worked example, computing WER with jiwer, normalization pitfalls, CER, and typical WER bands.
Jul 9, 2026 · 7 min read
The Best ASR Models in 2026: Open-Source and Commercial Compared
The best ASR models in 2026 compared: Whisper, NVIDIA Canary and Parakeet, Deepgram, AssemblyAI. Accuracy, languages, licenses, and how to choose.
Jul 2, 2026 · 7 min read
Speaker Diarization: How 'Who Spoke When' Actually Works
Speaker diarization explained: the VAD → embedding → clustering pipeline, end-to-end models, tools like pyannote and WhisperX, and the DER metric.
Jul 2, 2026 · 6 min read
15 Best Open-Source Speech Datasets for ASR and TTS (2026)
The 15 best open-source speech datasets for ASR and TTS in 2026: sizes, languages, licenses, and honest notes on where open data falls short.
Jul 1, 2026 · 7 min read
Code-Switching: What It Is and Why It Breaks Speech Recognition
What is code switching? Definition, linguistic types, real examples like Hinglish and Spanglish, and why it remains ASR's hardest everyday problem.
Jun 26, 2026 · 7 min read
What Is Voice Activity Detection (VAD)? How It Works and Why It Matters
Voice activity detection (VAD) explained: how energy-based and ML-based VAD works, where it sits in ASR and voice-agent pipelines, and how to evaluate it.
Jun 24, 2026 · 7 min read
What Is Speech Synthesis? From Formant Synthesis to Neural TTS
What is speech synthesis? How TTS evolved from formant and concatenative systems to neural models like VITS, and why training data now decides quality.
Jun 18, 2026 · 8 min read
What Is Audio Annotation? Types, Process, and Best Practices
Audio annotation explained: transcription, diarization, timestamps, and acoustic events, plus QA methods, tools, cost drivers, and build-vs-buy tradeoffs.
Jun 18, 2026 · 6 min read
Conversational vs. Scripted Speech Data: Which Does Your Model Need?
Conversational speech datasets vs. scripted read speech: acoustic differences, the WER gap on spontaneous speech, and which to use for ASR, TTS, and voice AI.
Jun 4, 2026 · 6 min read
What Is Automatic Speech Recognition (ASR)? A Practical Guide
What is automatic speech recognition? A practical ASR definition, how modern speech recognition works, WER explained, and the training data behind it.
Jun 4, 2026 · 6 min read
How Much Audio Data Do You Need to Train an ASR Model?
Size an ASR data project with a held-out test set, a staged pilot and clear acceptance criteria. Includes published examples and a collection brief.
May 20, 2026 · 7 min read
TTS Datasets: Choose Text-to-Speech Training Data
Separate training, adaptation and reference audio. Check transcripts, recording quality and model fit, then write a TTS collection brief.
May 6, 2026 · 7 min read
How to Buy AI Training Data: A Practical Playbook (2026)
How to buy AI training data without getting burned: provider types, pricing models, consent and license checks, red flags, and a procurement checklist.