add alternate windows tts

README.md

@@ -1,3 +1,13 @@
 Contents edited from <https://www.howtostudykorean.com> is at [/docs/howtostudykorean/](/docs/howtostudykorean/).
 
 For specifics of how this is created, see <https://git.polv.cc/polv/zh-grammar#how-it-works-for-android>
+
+## TTS
+
+For Windows TTS, I don't like Korean language support pack sound, so I use
+
+```shell
+docker run -it -p 5500:5500 synesthesiam/opentts:ko
+```
+
+It's required to have Docker running.