Improved preference paneMountain Lion makes it easier to customize your settings with the redesigned Accessibility pane in System Preferences.
Accessibility pane available from anywhereYou can access the Accessibility pane from anywhere on your Mac with the Command-Option-F5 keyboard shortcut.
New braille display supportMountain Lion supports 14 new braille displays.
Drag and drop using modifier keysDrag and drop with VoiceOver now supports modifier keys such as Command and Option, allowing you to execute different actions based on the context.
Reorder tablesYou can now reorder tables by column headers using VoiceOver.
Drag items to hotspotsYou can now drag items to hotspots using VoiceOver.
Support for press and hold buttonsVoiceOver in Mountain Lion supports press and hold buttons.
Wireless mirroringSend what’s on your Mac screen to an HDTV wirelessly with Apple TV. Mirroring is great for classrooms, conference rooms, and your living room.
High definitionAirPlay Mirroring sends a video stream automatically optimized for the HD capabilities of your Mac and Apple TV. It supports up to 1080p HD.
Automatic detectionWhen a Mac with Mountain Lion detects an Apple TV on the same network, the AirPlay Mirroring menu item appears in the menu bar.
Menu itemTo wirelessly mirror your Mac to your HDTV, click the AirPlay Mirroring menu item and choose your Apple TV. Use the menu to select a different Apple TV on your network and set resolution matching.
Resolution matchingAirPlay Mirroring scales the contents of your Mac desktop to fit on your HDTV. For a sharper image, choose to set the resolution of your desktop to best match that of your Apple TV.
Seamless integration with iTunesWhen you play movies or TV shows with iTunes on your Mac, AirPlay Mirroring will automatically switch to a full-screen AirPlay experience on your HDTV.
Encrypted streamingAirPlay Mirroring uses encryption to securely send what’s on your Mac to your Apple TV.
Audio supportWith AirPlay Mirroring, audio from your Mac is wirelessly sent to your Apple TV. You can use this feature independent of AirPlay Mirroring by selecting your Apple TV in the Sound pane of System Preferences.
High performanceAirPlay Mirroring takes advantage of advanced hardware video encoding to deliver high-definition mirroring efficiently and optimize processor use.
Rename from the title barRename a document without leaving the app. Just click the filename in the title bar and choose Rename from the document menu.
Revert to last savedEasily revert to the last saved version of a document to instantly undo all changes you made since you last saved the document.
Move to iCloudInstantly move iCloud-supported documents to iCloud from the document menu.
Prompt to save when closing a documentThe new “Ask to keep changes when closing a document” preference prompts you to keep or discard changes when closing a document.
Untitled documents in the cloudUntitled iCloud-supported documents are stored in iCloud so they’re available on all your devices.
Keyboard shortcut for DuplicateQuickly duplicate a document using the Command-Shift-S keyboard shortcut.
Keyboard shortcut for Save AsUse Command-Shift-Option-S to save a document using a different name and location.
Share buttonBuilt into many Mountain Lion apps, the Share button reveals a menu of sharing services appropriate for the application you’re using.
Share sheetsShare sheets appear in the app you’re using, so you can share quickly and easily — there’s no need to switch to another app and drag in a file.
Share menu servicesWhen you click the Share button, the Share menu presents services that are relevant to the app you’re using and the type of file you’re sharing.
Share anythingWith built-in sharing, it’s easy to share photos, videos, links, and documents from the apps you use to view them. Share using Mail, Messages, and AirDrop. And share directly to Twitter, Facebook, Vimeo, and Flickr.
Single sign-onSign in once to Twitter, Facebook, Vimeo and Flickr and your Mac is all set up to share right from the apps that support it.
Calendar sidebarClick the Calendars button to keep a list of all your calendars accessible in a sidebar.
Search suggestionsWhen you’re searching for an event, Calendar offers suggestions so it’s easy to find what you’re looking for.
Search tokensWhen you select a suggestion, Calendar creates a search token displaying a list of events that contain a match. Combine multiple tokens to refine a search.
New date pickerThe new date picker in the inspector displays a mini calendar so you can easily change the date of an event.
Event notificationsCalendar notifies you with an alert when an event is about to occur. Open Notification Center to see a list of upcoming events.
Groups columnContacts includes a new groups column, which always gives you quick access to your contact groups.
Unified viewContacts brings information about your contacts together and displays it on one card — even across multiple services. So if you have a friend’s phone number in Yahoo! and his email address in iCloud, Contacts creates one entry.
Share buttonEasily share contact information to Mail, Messages, or AirDrop from the Share button in Contacts.
Widget browserDashboard includes a new widget browser that makes it even easier to find a widget.
Search widgetsQuickly find widgets with the new search field. In the widget browser, start typing the name of the widget and Dashboard displays the results. Click the widget to add it to your Dashboard.
Create folders of widgetsOrganize your widgets into folders in the widget browser.
Talk anywhere you can typeOS X now supports Dictation. So wherever you can type, you can use your voice instead. Just select a text field and turn Dictation on. Use the keyboard shortcut — press the Function key twice — or choose Dictation from the Edit menu in any app. When you’re finished speaking, click Done. Dictation converts your words into text.
Works with any appDictation works with text fields in any OS X app — no additional third-party developer support is required.
Works with ContactsJust say your friend’s name, and Dictation knows who you mean. It works with information in the Contacts app to recognize and spell names accurately, even if they have unusual spellings.
Keyboard shortcutPress the Function key twice to start Dictation. Press it twice again when you’re done speaking.
No setup or training requiredNo setup or special training is required. Dictation just works. The more you use it, the better it understands you. Dictation learns the characteristics of your voice and adapts to your accent.
Works out of the boxDictation uses the built-in microphone on your Mac, so it works as soon as you start speaking. You can also use an additional microphone.
Dictate commandsDictation understands basic text-related commands such as “all caps,” “new paragraph,” and “new line.” When you say “period,” “comma,” “question mark,” or “exclamation point,” Dictation punctuates for you.
LanguagesDictation supports English (U.S., UK, and Australia), French, German, and Japanese. When your system is set to one of these languages, it automatically enters the right text.
Swipe between pagesSwipe left or right on the trackpad to navigate through your history in Dictionary.
New dictionariesThe Dictionary application in Mountain Lion includes Simplified Chinese, Spanish, and German definition dictionaries.
Single sign-onSign in once and your Mac is all set up to share even easier to Facebook, right from your apps. It sets up Notification Center and Contacts to work with Facebook, too. And you can post to Facebook without signing in again.
Facebook notificationsWhen you are signed in to Facebook, you can see your Facebook notifications in Notification Center.
Facebook Share sheetWhen you select Facebook from the Share menu, you see the Facebook Share sheet. It’s a handy card that includes the content you’re posting and makes it easy to add a comment. When you post a photo, you can add it to one of your albums.
LocationLet your Facebook friends know where you are. Click the location indicator in the Facebook Share sheet and add a location to your post.
Facebook friends in ContactsWhen you’re set up for Facebook in Mountain Lion, it adds your Facebook friends to Contacts — with profile photos and contact information. When friends update their information on Facebook, it’s automatically updated in Contacts.
Add profile photosYou can add profile photos for contacts who aren’t Facebook friends by choosing Update Contacts in the Facebook settings of Mail, Contacts, and Calendar.
Facebook integration coming this fall.