docs(readme): update

README.md

@@ -2,6 +2,52 @@
 
 > Your Text-to-Speech Services, All-in-One.
 
+## Features
+
+unSpeech lets you use other online TTS in OpenAI-compatible format.
+
+- OpenAI
+- ElevenLabs
+
+## Getting Started
+
+### Build
+
+unSpeech is not released yet, you need to build it from source code:
+
+> require `go` 1.23+
+
+```bash
+git clone https://github.com/moeru-ai/unspeech.git
+cd unspeech
+go build -o ./result/unspeech ./cmd/unspeech
+```
+
+### Run
+
+```bash
+# http server started on [::]:5933
+./result/unspeech
+```
+
+### Client
+
+You can use unSpeech with most OpenAI clients.
+
+###### [`@xsai/generate-speech`](https://github.com/moeru-ai/xsai)
+
+```ts
+import { generateSpeech } from '@xsai/generate-speech'
+
+const speech = await generateSpeech({
+  apiKey: 'YOUR_API_KEY',
+  baseURL: 'http://localhost:5933/v1/',
+  input: 'Hello, World!',
+  model: 'elevenlabs/eleven_multilingual_v2',
+  voice: '9BWtsMINqrJLrRacOk9x',
+})
+```
+
 ## License
 
 [AGPL-3.0](./LICENSE)