diff --git a/docs/LexerDevelopment.md b/docs/LexerDevelopment.md
index 3a389eb014..9057f4cd5a 100644
--- a/docs/LexerDevelopment.md
+++ b/docs/LexerDevelopment.md
@@ -495,6 +495,8 @@ The spec and the demo can be run using the `rake` command. You can run this by
 typing `bundle exec rake` at the command line. If everything works, you should
 see a series of dots. If you have an error, this will appear here, too.
 
+You can also run `bundle exec rake VERBOSE=1` to see all warnings.
+
 To see your visual sample, launch Rouge's visual test app by running
 `bundle exec rackup`. You can choose your sample from the complete list by going
 to <http://localhost:9292>.
diff --git a/tasks/check/specs.rake b/tasks/check/specs.rake
index 08c78ae8c8..2c6cd10920 100644
--- a/tasks/check/specs.rake
+++ b/tasks/check/specs.rake
@@ -2,7 +2,7 @@ namespace :check do
   Rake::TestTask.new(:specs) do |t|
     t.libs << "lib"
     t.ruby_opts << "-r./spec/spec_helper"
-    t.warning = !!$VERBOSE
+    t.warning = $VERBOSE || ENV["VERBOSE"]
     t.pattern = FileList['spec/**/*_spec.rb']
   end
 end