diff --git a/README.md b/README.md
index eb77779..0daf9d3 100644
--- a/README.md
+++ b/README.md
@@ -74,17 +74,27 @@ TelemetryDeck.signal("Database.updated", parameters: ["numberOfDatabaseEntries":
 
 TelemetryDeck will automatically send base parameters, such as:
 
+- TelemetryDeck.Accessibility.isBoldTextEnabled
+- TelemetryDeck.Accessibility.isDarkerSystemColorsEnabled
+- TelemetryDeck.Accessibility.isInvertColorsEnabled
+- TelemetryDeck.Accessibility.isReduceMotionEnabled
+- TelemetryDeck.Accessibility.isReduceTransparencyEnabled
+- TelemetryDeck.Accessibility.isSwitchControlEnabled
+- TelemetryDeck.Accessibility.isVoiceOverEnabled
+- TelemetryDeck.Accessibility.preferredContentSizeCategory
+- TelemetryDeck.Accessibility.shouldDifferentiateWithoutColor
+
 - TelemetryDeck.AppInfo.buildNumber
 - TelemetryDeck.AppInfo.version
 - TelemetryDeck.Device.architecture
 - TelemetryDeck.Device.modelName
 - TelemetryDeck.Device.operatingSystem
-- TelemetryDeck.Device.platform
 - TelemetryDeck.Device.orientation
+- TelemetryDeck.Device.platform
 - TelemetryDeck.Device.screenResolutionHeight
 - TelemetryDeck.Device.screenResolutionWidth
-- TelemetryDeck.Device.systemMajorVersion
 - TelemetryDeck.Device.systemMajorMinorVersion
+- TelemetryDeck.Device.systemMajorVersion
 - TelemetryDeck.Device.systemVersion
 - TelemetryDeck.Device.timeZone
 - TelemetryDeck.RunContext.isAppStore
@@ -94,9 +104,10 @@ TelemetryDeck will automatically send base parameters, such as:
 - TelemetryDeck.RunContext.language
 - TelemetryDeck.RunContext.targetEnvironment
 - TelemetryDeck.SDK.version
-- TelemetryDeck.UserPreference.region
-- TelemetryDeck.UserPreference.language
 - TelemetryDeck.UserPreference.colorScheme
+- TelemetryDeck.UserPreference.language
+- TelemetryDeck.UserPreference.layoutDirection
+- TelemetryDeck.UserPreference.region
 
 See our [Grand Renaming article](https://telemetrydeck.com/docs/articles/grand-rename/?source=github) for a full list.
 
diff --git a/Sources/TelemetryDeck/Signals/Signal.swift b/Sources/TelemetryDeck/Signals/Signal.swift
index 5330840..5a65ef4 100644
--- a/Sources/TelemetryDeck/Signals/Signal.swift
+++ b/Sources/TelemetryDeck/Signals/Signal.swift
@@ -94,11 +94,14 @@ public struct DefaultSignalPayload: Encodable {
             "TelemetryDeck.SDK.nameAndVersion": "SwiftSDK \(sdkVersion)",
             "TelemetryDeck.SDK.version": sdkVersion,
 
+            "TelemetryDeck.UserPreference.colorScheme": Self.colorScheme,
             "TelemetryDeck.UserPreference.language": Self.preferredLanguage,
+            "TelemetryDeck.UserPreference.layoutDirection": Self.layoutDirection,
             "TelemetryDeck.UserPreference.region": Self.region,
-            "TelemetryDeck.UserPreference.colorScheme": Self.colorScheme
         ]
 
+        parameters.merge(self.accessibilityParameters, uniquingKeysWith: { $1 })
+
         if let extensionIdentifier = Self.extensionIdentifier {
             // deprecated name
             parameters["extensionIdentifier"] = extensionIdentifier
@@ -114,6 +117,34 @@ public struct DefaultSignalPayload: Encodable {
 // MARK: - Helpers
 
 extension DefaultSignalPayload {
+    @MainActor
+    static var accessibilityParameters: [String: String] {
+        var a11yParams: [String: String] = [:]
+
+        #if os(iOS) || os(tvOS)
+        a11yParams["TelemetryDeck.Accessibility.isVoiceOverEnabled"] = "\(UIAccessibility.isVoiceOverRunning)"
+        a11yParams["TelemetryDeck.Accessibility.isReduceMotionEnabled"] = "\(UIAccessibility.isReduceMotionEnabled)"
+        a11yParams["TelemetryDeck.Accessibility.isBoldTextEnabled"] = "\(UIAccessibility.isBoldTextEnabled)"
+        a11yParams["TelemetryDeck.Accessibility.isInvertColorsEnabled"] = "\(UIAccessibility.isInvertColorsEnabled)"
+        a11yParams["TelemetryDeck.Accessibility.isDarkerSystemColorsEnabled"] = "\(UIAccessibility.isDarkerSystemColorsEnabled)"
+        a11yParams["TelemetryDeck.Accessibility.isReduceTransparencyEnabled"] = "\(UIAccessibility.isReduceTransparencyEnabled)"
+        if #available(iOS 13.0, *) {
+            a11yParams["TelemetryDeck.Accessibility.shouldDifferentiateWithoutColor"] = "\(UIAccessibility.shouldDifferentiateWithoutColor)"
+        }
+        a11yParams["TelemetryDeck.Accessibility.preferredContentSizeCategory"] = UIApplication.shared.preferredContentSizeCategory.rawValue
+            .replacingOccurrences(of: "UICTContentSizeCategory", with: "")  // replaces output "UICTContentSizeCategoryL" with "L"
+        a11yParams["TelemetryDeck.Accessibility.isSwitchControlEnabled"] = "\(UIAccessibility.isSwitchControlRunning)"
+        #elseif os(macOS)
+        a11yParams["TelemetryDeck.Accessibility.isVoiceOverEnabled"] = "\(NSWorkspace.shared.isVoiceOverEnabled)"
+        if let systemPrefs = UserDefaults.standard.persistentDomain(forName: "com.apple.universalaccess") {
+            a11yParams["TelemetryDeck.Accessibility.isReduceMotionEnabled"] = "\(systemPrefs["reduceMotion"] as? Bool ?? false)"
+            a11yParams["TelemetryDeck.Accessibility.isInvertColorsEnabled"] = "\(systemPrefs["InvertColors"] as? Bool ?? false)"
+        }
+        #endif
+
+        return a11yParams
+    }
+
     static var isSimulatorOrTestFlight: Bool {
         isSimulator || isTestFlight
     }
@@ -368,6 +399,18 @@ extension DefaultSignalPayload {
         #endif
     }
 
+    /// The user-preferred layout direction (left-to-right or right-to-left) based on the current language/region settings.
+    @MainActor
+    static var layoutDirection: String {
+        #if os(iOS) || os(tvOS)
+        return UIApplication.shared.userInterfaceLayoutDirection == .leftToRight ? "leftToRight" : "rightToLeft"
+        #elseif os(macOS)
+        return NSApp.userInterfaceLayoutDirection == .leftToRight ? "leftToRight" : "rightToLeft"
+        #else
+        return "N/A"
+        #endif
+    }
+
     /// The current devices screen resolution width in points.
     @MainActor
     static var screenResolutionWidth: String {