diff --git a/README.md b/README.md
index ff2717d..ad4b250 100644
--- a/README.md
+++ b/README.md
@@ -12,7 +12,7 @@ Supported Translator:
 
 ## ⚠️ Note for ChatGPT
 
-You need to apply a API key on [ChatGPT](https://platform.openai.com/account/api-keys).
+You need to apply an API key on [OpenAI API keys](https://platform.openai.com/account/api-keys).
 And write it to `$XDG_CONFIG_HOME/gtt/gtt.yaml` or `$HOME/.config/gtt/gtt.yaml`.
 
 ```yaml
@@ -92,10 +92,10 @@ Copy all text in source of translation window.
 Copy all text in destination of translation window.
 
 `<C-o>`
-Play sound on source of translation window.
+Play text to speech on source of translation window.
 
 `<C-p>`
-Play sound on destination of translation window.
+Play text to speech on destination of translation window.
 
 `<C-x>`
 Stop play sound.
diff --git a/ui.go b/ui.go
index cf42ffa..d2308ee 100644
--- a/ui.go
+++ b/ui.go
@@ -30,9 +30,9 @@ const (
 [#%[1]s]<C-r>[-]
 	Copy all text in destination of translation window.
 [#%[1]s]<C-o>[-]
-	Play sound on source of translation window.
+	Play text to speech on source of translation window.
 [#%[1]s]<C-p>[-]
-	Play sound on destination of translation window.
+	Play text to speech on destination of translation window.
 [#%[1]s]<C-x>[-]
 	Stop play sound.
 [#%[1]s]<C-t>[-]
@@ -500,7 +500,7 @@ func translateWindowHandler(event *tcell.EventKey) *tcell.EventKey {
 		}
 		dstOutput.SetText(srcText)
 	case tcell.KeyCtrlO:
-		// Play source sound
+		// Play text to speech on source of translation window.
 		if translator.LockAvailable() {
 			message := srcInput.GetText()
 			// Only play when message exist
@@ -517,7 +517,7 @@ func translateWindowHandler(event *tcell.EventKey) *tcell.EventKey {
 
 		}
 	case tcell.KeyCtrlP:
-		// Play destination sound
+		// Play text to speech on destination of translation window.
 		if translator.LockAvailable() {
 			message := dstOutput.GetText(false)
 			// Only play when message exist