CMU Sphinx vs Superwhisper

CMU Sphinx is a free, open-source toolkit for developers building speech applications. Its maintained components are PocketSphinx, a lightweight C speech recognizer library, and SphinxTrain, tools for acoustic model training. The toolkit is designed for efficient recognition on low-resource platforms, and its documented interfaces support keyword spotting, grammar and language-model searches, and word-level segmentation. Recognition requires acoustic and language models. The toolkit is language-independent, with prebuilt models listed for English, Chinese, French, Spanish, German and Russian. SphinxTrain supports adding a language through data collection and cleaning, model training and testing. Noise handling uses MFCC features, noise tracking and spectral subtraction. The BSD-like license permits commercial distribution. Possible applications include voice control, language learning, transcription, closed captioning, speech translation and voice search. Decoders require PCM input, so encoded audio must be converted before processing. The project documents a PocketSphinx Android library and demo, but cautions that its Android tutorial may no longer work with current tools. The homepage announces PocketSphinx 5.1.0.

Superwhisper turns speech into formatted text for use across applications. Its Super Mode reads the screen and adjusts dictated text to the current app, for example treating email as a message or coding prompts technically. It supports more than 100 languages, automatic language detection, and translation between languages. On-device speech models process audio locally, work without internet, and keep audio off the device's outbound path. With cloud models, audio and text pass through the Superwhisper proxy to the provider; the product says they are not retained for training. It works wherever text can be entered and names Slack, Cursor, and Notion, with coding plugins for Claude Code, OpenCode, Codex, and Pi. A CLI can search and export transcripts, report recording statistics, and start a local MCP server. Free includes voice-to-text, meeting recording and transcription, and email support. Pro costs $8.49 per month or $84.99 per year and adds audio and video transcription, cloud and local models, custom API keys, and priority support. Pro features can be tried for 3,000 words before free-tier features remain available.