NVIDIA Nemotron 3.5 Transcribe 30B-A4B

Nemotron 3.5 Transcribe is an open-weight, offline speech and audio model from NVIDIA. It turns recordings, together with text instructions and optional context, into text: multilingual transcription in 40 languages, speech translation, contextual transcription with domain vocabulary, speaker-attributed transcription, rich transcription, word timestamps, language identification, and audio question answering. It handles recordings up to one hour with a 65,536-token context.

Model summary

Parameters	34B total, ~4.3B active (including the audio encoder)
Architecture	Speech-Augmented Language Model: Nemotron 3.5 Lightning hybrid Mamba-2–Transformer MoE backbone with a Transformer ASR encoder, a Nemotron-3-Diarization speaker encoder and a CTC timestamp head
Precision	BF16
Context	65,536 tokens; recordings up to 1 hour
Languages	40
Speculative decoding	Native Multi-Token Prediction (MTP)
License	OpenMDW-1.1

Results at a glance

Error rates in percent, lower is better (NVIDIA, October 2026).

Capability	Benchmark	Nemotron 3.5 Transcribe	Next best open-weight
English ASR	Open ASR Leaderboard, 9 sets (mean WER)	4.71	Qwen3-ASR-1.7B 4.94
Long-form ASR	Open ASR Leaderboard, long-form (mean WER)	10.98	Parakeet-TDT-0.6B-v3 13.37
Multilingual ASR	Multilingual Open ASR Leaderboard, 7 languages (mean WER)	4.62	Qwen3-ASR-1.7B 6.49
Multi-speaker ASR	AMI, CALLHOME, Mixer 6, NOTSOFAR-1 (mean cpWER)	15.80	DiCoW v3.3 + DiariZen 16.83

Prompting

Pick the transcription style with the instruction; keep the system prompt empty for transcription and translation.

What you need	Instruction
Verbatim words	Audio transcription. Language: as spoken. Wording: verbatim, including fillers and repetitions. Formatting: punctuation and capitalization. Output: transcript only.
Readable text	Audio transcription. Language: as spoken. Wording: omit fillers and accidental repetitions; keep the remaining spoken wording unchanged. Formatting: punctuation and capitalization. Output: transcript only.
Domain vocabulary	Transcribe with punctuation and capitalization. Context terms: <names and terms>.
Who said what	Transcribe verbatim, including fillers. Write numbers as spoken, without punctuation or capitalization. Start every speaker turn with <spk:0>, <spk:1>, etc. Keep one stable tag per speaker. Output only the speaker-tagged transcript.
Translation	Please translate the given speech to <target language>.

Use temperature 0 with reasoning off for transcription, translation and language identification.

This is an offline model: it is not a real-time streaming ASR service. For streaming transcription, see Nemotron 3.5 ASR Streaming Multilingual.

Ethical considerations

Speaker labels distinguish speakers within a recording; they do not establish real-world identity. NVIDIA believes Trustworthy AI is a shared responsibility. Developers should make sure the model meets the requirements of their use case and addresses unforeseen product misuse.

Use of this model is governed by the OpenMDW License Agreement, version 1.1.