diff --git a/lib/text_cleaner.rb b/lib/text_cleaner.rb
index 656fba28f..1b0659cb0 100644
--- a/lib/text_cleaner.rb
+++ b/lib/text_cleaner.rb
@@ -31,9 +31,9 @@ class TextCleaner
     # Replace ????? with a single ?
     text.gsub!(/\?+/, '?') if opts[:deduplicate_question_marks]
     # Replace all-caps text with regular case letters
-    text = text.mb_chars.downcase if opts[:replace_all_upper_case] && (text =~ /[A-Z]+/) && (text == text.upcase)
+    text = text.mb_chars.downcase.to_s if opts[:replace_all_upper_case] && (text =~ /[A-Z]+/) && (text == text.upcase)
     # Capitalize first letter, but only when entire first word is lowercase
-    text.sub!(/\A([a-z]*)\b/) { |first| first.capitalize } if opts[:capitalize_first_letter]
+    text = text.mb_chars.capitalize.to_s if opts[:capitalize_first_letter] && text.split(' ').first == text.split(' ').first.mb_chars.downcase
     # Remove unnecessary periods at the end
     text.sub!(/([^.])\.+(\s*)\z/, '\1\2') if opts[:remove_all_periods_from_the_end]
     # Remove extraneous space before the end punctuation