Menu accessibility tab doc update

src/pages/components/menu/accessibility.mdx

@@ -6,10 +6,80 @@ tabs: ['Usage', 'Style', 'Code', 'Accessibility']
 
 import A11yStatus from 'components/A11yStatus';
 
-<InlineNotification>
+<PageDescription>
 
-**Coming soon!** This page is a work in progress.
+No accessibility annotations are needed for menus, but keep these considerations
+in mind if you are modifying Carbon or creating a custom component.
 
-</InlineNotification>
+</PageDescription>
+
+<AnchorLinks>
+
+<AnchorLink>What Carbon provides</AnchorLink>
+<AnchorLink>Development considerations</AnchorLink>
+
+</AnchorLinks>
+
+## What Carbon provides
+
+Carbon bakes keyboard operation into its components, improving the experience of
+blind users and others who operate via keyboard. Carbon also incorporates other
+accessibility considerations, some of which are described below.
+
+### Keyboard interaction
+
+The menu is reached by tab. When the menu is open, the first item takes focus.
+The menu items are navigated using the `Up` and `Down` arrow keys.
+
+<Row>
+
+<Column colLg={8}>
+
+![example of menu keyboard interaction](images/accessibility-menu-1.png)
+
+<Caption>
+  Menu is reached by tab and when opened, the first menu item takes focus. Arrow
+  keys move focus.
+</Caption>
+
+</Column>
+</Row>
+
+Pressing `Space` or `Enter` on a focused menu item activates it and collapses
+the menu or activates the sub-menu. An activated menu item can have different
+results depending on its functionality. If the item is a link, it launches the
+selection. If the item is selectable, it selects or deselects the item. If
+multiple items are selectable in a menu, that is one of many, selection switches
+to that item, and it shows up as selected when the menu is opened again.
+
+<Row>
+<Column colLg={8}>
+
+![example of menu keyboard interaction](images/accessibility-menu-2.png)
+
+<Caption>
+  Space and Enter keys activates/selects/deselects the menu item with focus.
+</Caption>
+
+</Column>
+</Row>
+
+## Development considerations
+
+Keep these considerations in mind if you are modifying Carbon or creating a
+custom component.
+
+- Each menu, including nested menus, are `ul` elements with `role="menu"`
+- Menu items are `li` elements with `role="menuitem"`
+- If a Menu item contains a sub-menu, it is given `aria-haspopup="true"` and
+  `aria-expanded` of true or false depending on if the sub-menu is open/visible.
+- Selectable menu items are given `role="menuitemcheckbox"`
+- Menu item groups are 'li' elements with `role="group"`
+- Menu item radio groups get `role="menuitemradio"`
+- Menu items with really long label can get truncated depending on screen sizes.
+  This label will be exposed by a browser rendered tooltip on hover or focus.
+- Menu implements the
+  [menu design pattern](https://www.w3.org/WAI/ARIA/apg/patterns/menubar/)
+  defined in the ARIA Authoring Practices Guide (APG).
 
 <A11yStatus layout="table" components="Menu" />

src/pages/components/menu/usage.mdx

@@ -328,7 +328,8 @@ including the direction of the caret and keyboard shortcuts.
 #### Overflow
 
 Consider using short and precise labels for menu items. However, when deciding
-to truncate long menu items, use a tooltip on hover to reveal the full text.
+to truncate long menu items, a browser rendered title tooltip will reveal the
+full text on hover.
 
 <Row>
 <Column colLg={8}>