diff --git a/extkeys/mnemonic.go b/extkeys/mnemonic.go
index 0d59e6414..1509d14b0 100644
--- a/extkeys/mnemonic.go
+++ b/extkeys/mnemonic.go
@@ -240,7 +240,7 @@ func (m *Mnemonic) ValidMnemonic(mnemonic string, language Language) bool {
 
 // WordList returns list of words for a given language
 func (m *Mnemonic) WordList(language Language) (*WordList, error) {
-	if m.wordLists[language] == nil {
+	if int(language) < 0 || int(language) > len(m.wordLists)-1 || m.wordLists[language] == nil {
 		return nil, fmt.Errorf("language word list is missing (language id: %d)", language)
 	}
 	return m.wordLists[language], nil
diff --git a/extkeys/mnemonic_test.go b/extkeys/mnemonic_test.go
index 4953ed0d8..fbcf4915d 100644
--- a/extkeys/mnemonic_test.go
+++ b/extkeys/mnemonic_test.go
@@ -29,6 +29,22 @@ func TestNewMnemonic(t *testing.T) {
 	}
 }
 
+func TestMnemonic_WordList(t *testing.T) {
+	m := NewMnemonic("")
+	_, err := m.WordList(EnglishLanguage)
+	if err != nil {
+		t.Errorf("expected WordList to return WordList without errors, got: %s", err)
+	}
+
+	indexes := []Language{-1, Language(len(m.wordLists))}
+	for _, index := range indexes {
+		_, err := m.WordList(index)
+		if err == nil {
+			t.Errorf("expected WordList to return an error with index %d", index)
+		}
+	}
+}
+
 // TestMnemonicPhrase
 func TestMnemonicPhrase(t *testing.T) {