diff --git a/loader.go b/loader.go
index b6f0f29..f1fbe06 100644
--- a/loader.go
+++ b/loader.go
@@ -132,9 +132,6 @@ func flattenWithGrammar(prefix string, data map[string]any, out map[string]Messa
 				if gerund, ok := v["gerund"].(string); ok {
 					forms.Gerund = gerund
 				}
-				if forms.Past == "" || forms.Gerund == "" {
-					continue
-				}
 				grammar.Verbs[core.Lower(verbName)] = forms
 				continue
 			}
diff --git a/loader_test.go b/loader_test.go
index be4a570..b51fdfe 100644
--- a/loader_test.go
+++ b/loader_test.go
@@ -208,11 +208,15 @@ func TestFlattenWithGrammar(t *testing.T) {
 	if _, ok := grammar.Verbs["publish_draft"]; ok {
 		t.Error("verb should be stored under explicit base, not JSON key")
 	}
-	if _, ok := grammar.Verbs["partial_past"]; ok {
-		t.Error("incomplete verb entry with only past should be skipped")
+	if v, ok := grammar.Verbs["partial_past"]; !ok {
+		t.Error("incomplete verb entry with only past should be extracted")
+	} else if v.Past != "partialed" || v.Gerund != "" {
+		t.Errorf("partial_past forms = %+v, want Past only", v)
 	}
-	if _, ok := grammar.Verbs["partial_gerund"]; ok {
-		t.Error("incomplete verb entry with only gerund should be skipped")
+	if v, ok := grammar.Verbs["partial_gerund"]; !ok {
+		t.Error("incomplete verb entry with only gerund should be extracted")
+	} else if v.Past != "" || v.Gerund != "partialing" {
+		t.Errorf("partial_gerund forms = %+v, want Gerund only", v)
 	}
 	if _, ok := messages["gram.verb.partial_past"]; ok {
 		t.Error("gram.verb.partial_past should not be flattened into messages")
diff --git a/service_test.go b/service_test.go
index 94f915b..e99f960 100644
--- a/service_test.go
+++ b/service_test.go
@@ -348,6 +348,48 @@ func TestServiceSubjectCountPlurals(t *testing.T) {
 	}
 }
 
+func TestServiceLoadJSONPartialVerbForms(t *testing.T) {
+	svc, err := New()
+	if err != nil {
+		t.Fatalf("New() failed: %v", err)
+	}
+
+	const lang = "zz"
+	prevDefault := Default()
+	prevGrammar := GetGrammarData(lang)
+	SetDefault(svc)
+	t.Cleanup(func() {
+		SetDefault(prevDefault)
+		SetGrammarData(lang, prevGrammar)
+	})
+
+	svc.currentLang = lang
+
+	if err := svc.loadJSON(lang, []byte(`{
+		"gram": {
+			"verb": {
+				"render": { "past": "rendered" },
+				"stream": { "gerund": "streaming" }
+			}
+		}
+	}`)); err != nil {
+		t.Fatalf("loadJSON() failed: %v", err)
+	}
+
+	if v, ok := GetGrammarData(lang).Verbs["render"]; !ok || v.Past != "rendered" || v.Gerund != "" {
+		t.Fatalf("partial past verb not loaded correctly: %+v", v)
+	}
+	if v, ok := GetGrammarData(lang).Verbs["stream"]; !ok || v.Past != "" || v.Gerund != "streaming" {
+		t.Fatalf("partial gerund verb not loaded correctly: %+v", v)
+	}
+	if got := PastTense("render"); got != "rendered" {
+		t.Fatalf("PastTense(render) = %q, want %q", got, "rendered")
+	}
+	if got := Gerund("stream"); got != "streaming" {
+		t.Fatalf("Gerund(stream) = %q, want %q", got, "streaming")
+	}
+}
+
 func TestServiceTemplatesSupportGrammarFuncs(t *testing.T) {
 	svc, err := New()
 	if err != nil {