Document markup and improve choice tags

public/locales/en_US.json

@@ -1,5 +1,5 @@
 {
-  "title.byAuthor": "by {{author}}",
+  "title.byAuthor": "{{author}}",
   "title.version": "Version {{version}}",
   "title.fastForwardHint": "click on page or press spacebar to fast forward text animation",
   "title.continueHint": "click on page or press spacebar to continue",
@@ -21,7 +21,8 @@
   "options.title": "Options",
   "options.close": "Close",
   "options.applicationSettings": "Application Settings",
-  "options.language": "Language",
+  "options.language": "UI Language",
+  "options.gameLanguage": "Game Text Language",
   "options.speech": "Speech",
   "options.enableSpeech": "Enable text to speech",
   "options.provider": "Provider",
@@ -33,8 +34,34 @@
   "options.speechVolume": "Speech Volume",
   "options.musicVolume": "Music Volume",
   "options.sfxVolume": "Sound Effects Volume",
+  "options.musicDucking": "Music Ducking",
+  "options.muteMasterVolume": "Disable master audio",
+  "options.unmuteMasterVolume": "Enable master audio",
+  "options.muteSpeechVolume": "Disable speech audio",
+  "options.unmuteSpeechVolume": "Enable speech audio",
+  "options.muteMusicVolume": "Disable music audio",
+  "options.unmuteMusicVolume": "Enable music audio",
+  "options.muteSfxVolume": "Disable sound effects",
+  "options.unmuteSfxVolume": "Enable sound effects",
+  "options.disableMusicDucking": "Disable music ducking",
+  "options.enableMusicDucking": "Enable music ducking",
   "options.elevenLabsSettings": "ElevenLabs API Settings",
   "options.openAiSettings": "OpenAI API Settings",
   "options.apiKey": "API Key",
-  "options.apiUrl": "API URL"
+  "options.apiUrl": "API URL",
+  "credits.button": "credits",
+  "credits.buttonTitle": "Show credits and third-party licenses",
+  "credits.title": "Credits and Licenses",
+  "credits.close": "Close",
+  "credits.loading": "Loading credits...",
+  "credits.loadFailed": "Credits and license notices could not be loaded.",
+  "popup.ok": "OK",
+  "popup.endingTitle": "Ending reached",
+  "popup.errorTitle": "Game ended",
+  "popup.achievementTitle": "Achievement",
+  "popup.alertTitle": "Hint",
+  "popup.defaultEnding": "You reached an ending.",
+  "popup.defaultError": "The game ended because of an unrecoverable error.",
+  "popup.defaultAchievement": "Achievement unlocked.",
+  "popup.defaultAlert": "Hint"
 }