STT
~3 min read
Concept & How It Works
Why Does It Exist?
Voice is the most natural interface for hands-free scenarios — driving, cooking, customer support calls. STT bridges human speech and LLM text processing.
Real-World Analogy
STT is a court stenographer — they listen to spoken words and type them out in real time for the record.
Visual Workflows
What is STT?
Example
Scenario
User speaks into mobile app → streaming STT converts to text in 300ms → text sent to support agent → agent responds → TTS plays answer.
Solution
In Voice & Multimodal Agents, apply STT to this scenario: User speaks into mobile app → streaming STT converts to text in 300ms → text sent to support agent → agent responds → TTS plays answer. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.
Practice Task
Do this before moving to the next module — reading alone is not enough.
Open the Code Walkthrough below and run it locally. Change one parameter related to STT (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.
Code Walkthrough
Highlighted lines show where STT happens in the code.
1from openai import OpenAI # import dependencies2
3client = OpenAI() # create API client4
5def transcribe(audio_file_path: str) -> str: # define a reusable function6 with open(audio_file_path, "rb") as f:7 transcript = client.audio.transcriptions.create( # call the API8 model="whisper-1",9 file=f,10 response_format="text",11 )12 return transcript # return the resultCommands to Remember
Commands to Remember
pip install openai # vision, audio, and TTS APIspip install pypdf # PDF ingestion for document agents
Common Mistakes
- Treating STT as a black box without evaluation
- Ignoring cost and latency in production
- Skipping error handling for stt
Cheat Sheet
Quick recap — the most important points from this module.
Cheat Sheet
quick ref- •STT
- •WER
- •Whisper
- •Streaming STT