diff --git a/README.md b/README.md
index 4ef3792..de49fe6 100644
--- a/README.md
+++ b/README.md
@@ -51,12 +51,16 @@ Use Azure TTS as an example:
 ```python
 from tetos.azure import AzureSpeaker
 
-speaker = AzureSpeaker(speech_key='...', service_region='...')
+speaker = AzureSpeaker(speech_key='...', speech_region='...')
 speaker.say('Hello, world!', 'output.mp3')
 ```
 
 The initialization parameters may be different for other providers.
 
+## Behind a proxy
+
+TeTos respects the proxy environment variables `HTTP_PROXY`, `HTTPS_PROXY`, `ALL_PROXY` and `NO_PROXY`.
+
 ## License
 
 [Apache License 2.0](https://www.apache.org/licenses/LICENSE-2.0)