diff --git a/Library/Homebrew/cask/lib/hbc/dsl.rb b/Library/Homebrew/cask/lib/hbc/dsl.rb
index 9d229e2880..652f37c193 100644
--- a/Library/Homebrew/cask/lib/hbc/dsl.rb
+++ b/Library/Homebrew/cask/lib/hbc/dsl.rb
@@ -134,9 +134,7 @@ module Hbc
       end
 
       MacOS.languages.map(&Locale.method(:parse)).each do |locale|
-        key = @language_blocks.keys.detect do |strings|
-          strings.any? { |string| locale.include?(string) }
-        end
+        key = locale.detect(@language_blocks.keys)
 
         next if key.nil?
 
diff --git a/Library/Homebrew/locale.rb b/Library/Homebrew/locale.rb
index c430d11b64..38860403fe 100644
--- a/Library/Homebrew/locale.rb
+++ b/Library/Homebrew/locale.rb
@@ -68,6 +68,11 @@ class Locale
   end
   alias == eql?
 
+  def detect(locale_groups)
+    locale_groups.detect { |locales| locales.any? { |locale| eql?(locale) } } ||
+      locale_groups.detect { |locales| locales.any? { |locale| include?(locale) } }
+  end
+
   def to_s
     [@language, @region, @script].compact.join("-")
   end