diff --git a/config.go b/config.go
index 99391c3..a9b1d8e 100644
--- a/config.go
+++ b/config.go
@@ -4,7 +4,7 @@ import (
 	"os"
 )
 
-// search XDG_CONFIG_HOME or $HOME/.config
+// Search XDG_CONFIG_HOME or $HOME/.config
 func configInit() {
 	var defaultConfigPath string
 
@@ -37,6 +37,7 @@ func configInit() {
 	translator.dstLang = config.GetString("destination.language")
 }
 
+// Check if need to modify config file when quit program
 func updateConfig() {
 	changed := false
 
diff --git a/language.go b/language.go
index 114b3c2..69b6ae8 100644
--- a/language.go
+++ b/language.go
@@ -1,5 +1,6 @@
 package main
 
+// https://cloud.google.com/translate/docs/languages
 var (
 	Lang = []string{
 		"Afrikaans",
diff --git a/translator.go b/translator.go
index 18a4fc0..c20adf6 100644
--- a/translator.go
+++ b/translator.go
@@ -86,6 +86,7 @@ func (t *Translator) Translate(message string) (string, error) {
 		}
 		return translated, nil
 	}
+
 	return "", errors.New("Translation not found")
 }
 
diff --git a/ui.go b/ui.go
index abb3f60..d99a36a 100644
--- a/ui.go
+++ b/ui.go
@@ -103,7 +103,7 @@ func updateAllColor() {
 	updateNonConfigColor()
 }
 
-// update title and option
+// Update title and option
 func updateTitle() {
 	srcBox.SetTitle(translator.srcLang)
 	dstBox.SetTitle(translator.dstLang)
@@ -239,7 +239,7 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 		}
 		dstBox.SetText(src_text)
 	case tcell.KeyCtrlO:
-		// play source sound
+		// Play source sound
 		if translator.soundLock.Available() {
 			message := srcBox.GetText()
 			if len(message) > 0 {
@@ -254,7 +254,7 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 
 		}
 	case tcell.KeyCtrlP:
-		// play destination sound
+		// Play destination sound
 		if translator.soundLock.Available() {
 			message := dstBox.GetText(false)
 			if len(message) > 0 {
@@ -268,7 +268,7 @@ func translatePageHandler(event *tcell.EventKey) *tcell.EventKey {
 			}
 		}
 	case tcell.KeyCtrlX:
-		// stop play sound
+		// Stop play sound
 		translator.soundLock.stop = true
 	}