Added default locale fallback when loading supported locales on the ContentViewModel view model in the Sample app target.

Apps/Attendi/View Models/ContentViewModel.swift

@@ -48,11 +48,18 @@ extension ContentView {
         // MARK: Methods
 
         /// Loads the locales the transcriber supports into ``locales``, sorted by their localized names, and aligns ``locale`` with the
-        /// supported equivalent of its current value so the locale picker starts with a valid selection.
+        /// supported equivalent of its current value — falling back to the supported equivalent of a default locale when none exists —
+        /// so the locale picker starts with a valid selection.
         func load() async {
             locales = await SpeechTranscriber.supportedLocales.sorted {
                 name(for: $0).localizedStandardCompare(name(for: $1)) == .orderedAscending
             }
+
+            if let equivalent = await SpeechTranscriber.supportedLocale(equivalentTo: locale) {
+                locale = equivalent
+            } else if let fallback = await SpeechTranscriber.supportedLocale(equivalentTo: .byDefault) {
+                locale = fallback
+            }
         }
         
         /// Returns the localized name of a locale for the locale picker.
@@ -62,7 +69,8 @@ extension ContentView {
         func name(
             for locale: Locale
         ) -> String {
-            Locale.current
+            Locale
+                .current
                 .localizedString(
                     forIdentifier: locale.identifier
                 )?.localizedCapitalized
@@ -86,3 +94,10 @@ extension ContentView {
     }
 
 }
+
+// MARK: - Constants
+
+private extension Locale {
+    /// The locale to fall back to when the transcriber supports no equivalent of the user's current locale.
+    static let byDefault: Locale = .init(identifier: "en_US")
+}