How Accurate Is AI Transcription? What Really Affects the Results
By the Speakmi team · Updated October 2, 2026 · 2 min read
AI transcription has improved dramatically, but it is not magic. Accuracy ranges from nearly perfect on a clear studio recording to frustrating on a noisy phone call. Knowing why helps you record better and decide how much proofreading a transcript needs.
How accuracy is measured
Researchers usually report word error rate (WER): the share of words that were wrongly inserted, deleted, or replaced compared with a human transcript. A lower number is better. Published scores come from test sets, so your results with a particular microphone, accent, or topic can differ in either direction. Treat any single percentage as a rough guide, not a promise.
The factors that matter most
- Audio quality. Background noise, echo, and distance from the microphone cause more errors than anything else.
- Overlapping speakers. When people talk over each other, models often merge or drop words.
- Accents and dialects. Models trained on large multilingual data cope well with many accents, but less common varieties are still harder.
- Vocabulary. Names, brands, medical terms, and slang are the words most likely to be misspelled.
- Language. Languages with less training data usually score lower than English, Spanish, or French.
Common mistakes to watch for
Speech models can occasionally produce text during long silences or music, repeat a phrase, or mishear similar-sounding words (for example "accept" and "except"). Numbers, dates, and negations such as "can" and "can't" deserve a second look because a single wrong word can reverse the meaning.
How to get cleaner transcripts
- Record in a quiet room and keep the microphone close to the speaker.
- Use a larger model when accuracy matters more than speed. In voice.speakmi, choose Balanced over Fast.
- Select the spoken language manually instead of relying on auto-detect.
- Trim long silences, intros, and music before transcribing.
- Proofread names and figures against a trusted source.
When a human transcriber is still better
For legal proceedings, medical records, and anything where an error has serious consequences, use AI for a fast first draft and have a person verify it. For meeting notes, study material, and subtitles, a quick read-through is usually enough.