> ## Documentation Index
> Fetch the complete documentation index at: https://docs.inworld.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Lexicon

Use this lexicon to quickly understand common acronyms and AI terms used in the Runtime.

## Speech recognition

| Term                             | Definition                                                                     |
| -------------------------------- | ------------------------------------------------------------------------------ |
| STT (Speech-to-Text)             | Converts spoken audio into text. Used to understand player speech.             |
| VAD (Voice Activity Detection)   | Detects when speech is present in an audio stream to start/stop sending audio. |
| AEC (Acoustic Echo Cancellation) | Reduces game audio leaking into the microphone input by cancelling echoes.     |

## Language models and reasoning

| Term                       | Definition                                                                                                                                                                                  |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| LLM (Large Language Model) | An AI model trained on massive amounts of text to understand and generate human-like language. LLMs can power capabilities like dialog generation, game state changes, reasoning, and more. |
| Intent                     | The inferred meaning or purpose behind an input. Often used in the context of inferring whether a user message falls under a certain intent, to trigger some action.                        |

## Knowledge and retrieval

| Term                                 | Definition                                                                              |
| ------------------------------------ | --------------------------------------------------------------------------------------- |
| Embedding                            | A numeric vector representation of text used to measure semantic similarity.            |
| Knowledge                            | Structured or unstructured information the character can reference during conversation. |
| RAG (Retrieval-Augmented Generation) | A technique that retrieves relevant knowledge (via embeddings) to ground LLM responses. |

## Speech synthesis

| Term                 | Definition                                                                                           |
| -------------------- | ---------------------------------------------------------------------------------------------------- |
| TTS (Text to Speech) | Converts generated text into spoken audio. Often paired with an LLM to generate a character's voice. |