diff --git a/src/calibre/gui2/tweak_book/spell.py b/src/calibre/gui2/tweak_book/spell.py
index 2b7cd96a4b..0b870f0871 100644
--- a/src/calibre/gui2/tweak_book/spell.py
+++ b/src/calibre/gui2/tweak_book/spell.py
@@ -493,8 +493,8 @@ class ManageUserDictionaries(Dialog):
                 'You must specify a language to import words'), show=True)
         words = set(filter(None, [x.strip() for x in str(w.toPlainText()).splitlines()]))
         lang = lc[0]
-        words = {(w, lang) for w in words} - self.current_dictionary.words
-        if dictionaries.add_to_user_dictionary(self.current_dictionary.name, words, DictionaryLocale(lang, None)):
+        words_with_lang = {(w, lang) for w in words} - self.current_dictionary.words
+        if dictionaries.add_to_user_dictionary(self.current_dictionary.name, words_with_lang, DictionaryLocale(lang, None)):
             dictionaries.clear_caches()
             self.show_current_dictionary()
             self.dictionaries_changed = True
diff --git a/src/calibre/spell/dictionary.py b/src/calibre/spell/dictionary.py
index 7e1ecad0c4..8d6f2a26df 100644
--- a/src/calibre/spell/dictionary.py
+++ b/src/calibre/spell/dictionary.py
@@ -291,7 +291,7 @@ class Dictionaries:
         wl = len(ud.words)
         if isinstance(word, (set, frozenset)):
             ud.words |= word
-            self.add_user_words(word, locale.langcode)
+            self.add_user_words({x[0] for x in word}, locale.langcode)
         else:
             ud.words.add((word, locale.langcode))
             self.add_user_words((word,), locale.langcode)