Whistle: Open-Source Speech-to-Text in 16.9 MB

ArticleJakub Mroz, Henry NdubuakuAnnouncement

Cactus Compute has released Whistle, a lightweight speech recognition model packaged into a single 16.9 MB file. Running on CPU without external dependencies, it shares its C++ engine with Needle to convert audio directly into tool calls.

Key points

  1. Compact 16.9 MB footprint designed for on-device deployment across mobile, wearables, microcontrollers, and browsers via WASI.
  2. Transcribes seven languages (English, German, French, Spanish, Italian, Dutch, Polish) on audio clips up to 30 seconds.
  3. Low latency achieving 11.1 ms time to first token on a 10-second clip (Apple M4 Pro CPU) with a decode speed of 1,319 tokens per second.
  4. Provides word timestamps, audio embeddings, and supports keyword biasing via an Aho-Corasick automaton.
  5. Co-loads alongside the Needle foundation model inside a single binary, mapping voice commands directly into JSON tool calls.

Why it matters

On-device speech recognition has historically required substantial memory and compute overhead. Whistle demonstrates that accurate multilingual transcription and voice-driven tool invocation can run locally on standard CPUs without cloud dependency or heavy runtimes.

Analysis

By sharing structural layers with Needle, Cactus Compute minimises execution redundancy in the C++ engine. In reported benchmarks against Whisper base and Moonshine tiny v2, Whistle demonstrates notable latency and throughput advantages, alongside lower word error rates on benchmarks like LibriSpeech and FLEURS. The availability of prebuilt binaries across 17 architectures—ranging from iOS to RISC-V—makes it a versatile candidate for privacy-conscious edge applications.

Found in

Summary generated by AI (Gemini 3.8 Flash, 9 October 2026). It may contain errors – the original source is authoritative.

Similar in content, found by the AI search.

  • X post:Mario Zechner

    Whistle: On-Device Speech-to-Text in Just 16.9 MB

    Mario Zechner highlights Whistle by Cactus, an open speech-to-text model requiring only 16.9 MB of storage. It runs CPU-only without external dependencies and supports transcription in seven languages.

    592bookmarks24.3kviews

    AI & LLMs· Tool

  • Repository:google-ai-edge/LiteRT-LM

    LiteRT-LM: Google's Open-Source Inference Framework for On-Device LLMs

    LiteRT-LM is an open-source inference orchestration layer from Google designed to run large language models directly on edge devices. It leverages GPU and NPU acceleration and powers on-device generative AI features in Chrome, Pixel Watch, and Chromebook Plus.

    6.4kstarsC++

    AI & LLMs· Tool

  • Repository:huggingface/speech-to-speech

    Hugging Face Speech to Speech: Modular Open-Source Voice Agent Pipeline

    Hugging Face has released speech-to-speech, a modular open-source framework designed to build voice agents with open-source models. The pipeline spans VAD, STT, LLM, and TTS, exposing the core OpenAI Realtime GA event set over WebSocket and WebRTC.

    13kstarsPython

    AI & LLMs· Tool

  • Repository:jamiepine/voicebox

    Voicebox: Open-Source Local AI Voice Studio and Dictation Tool

    Voicebox is a local-first, open-source voice studio combining text-to-speech, voice cloning, and system-wide dictation. It serves as a self-hosted alternative to proprietary cloud solutions such as ElevenLabs and WisprFlow.

    55.6kstarsTypeScript

    AI & LLMs· Tool

  • Repository:drumih/turbo-fieldfare

    TurboFieldfare: Gemma 4 26B-A4B Inference in 2 GB RAM on Apple Silicon

    TurboFieldfare is a dedicated Swift and Metal runtime designed to run Google's Gemma 4 26B-A4B on Apple Silicon Macs within an approximately 2 GB RAM budget. It avoids loading the full 14.3 GB model into memory by keeping only the 1.35 GB core and KV cache in RAM while streaming the required mixture-of-experts weights from SSD on demand.

    6.6kstarsSwift

    AI & LLMs· Tool

Let's talk about your project

Locations

  • Mattersburg
    Johann Nepomuk Bergerstraße 7/2/14
    7210 Mattersburg, Austria
  • Vienna
    Ungargasse 64-66/3/404
    1030 Wien, Austria

Parts of this content were created with the assistance of AI.