diff --git a/grammar.go b/grammar.go
index 889a15d..b77948f 100644
--- a/grammar.go
+++ b/grammar.go
@@ -163,6 +163,16 @@ func IrregularNouns() map[string]string {
 	return result
 }
 
+// Lower returns the lowercase form of s.
+func Lower(s string) string {
+	return core.Lower(s)
+}
+
+// Upper returns the uppercase form of s.
+func Upper(s string) string {
+	return core.Upper(s)
+}
+
 func getVerbForm(lang, verb, form string) string {
 	data := GetGrammarData(lang)
 	if data == nil || data.Verbs == nil {
@@ -782,8 +792,8 @@ func definiteArticleFromGrammarForms(data *GrammarData, lowerWord, originalWord,
 func TemplateFuncs() template.FuncMap {
 	return template.FuncMap{
 		"title":           Title,
-		"lower":           core.Lower,
-		"upper":           core.Upper,
+		"lower":           Lower,
+		"upper":           Upper,
 		"past":            PastTense,
 		"gerund":          Gerund,
 		"plural":          Pluralize,
diff --git a/grammar_test.go b/grammar_test.go
index 59dfd37..0ee4bf2 100644
--- a/grammar_test.go
+++ b/grammar_test.go
@@ -474,6 +474,15 @@ func TestQuote(t *testing.T) {
 	}
 }
 
+func TestCaseHelpers(t *testing.T) {
+	if got := Lower("HELLO"); got != "hello" {
+		t.Fatalf("Lower(%q) = %q, want %q", "HELLO", got, "hello")
+	}
+	if got := Upper("hello"); got != "HELLO" {
+		t.Fatalf("Upper(%q) = %q, want %q", "hello", got, "HELLO")
+	}
+}
+
 func TestArticlePhrase(t *testing.T) {
 	tests := []struct {
 		word string