diff --git a/init.go b/init.go
index c2a1af9..ccabb70 100644
--- a/init.go
+++ b/init.go
@@ -60,22 +60,26 @@ func NewConfig() (ConfigSection, error) {
  */
 func NewI18n(mainlang string) (i18n gt.Strings, err error) {
 	data, err := os.ReadFile(ZAS_I18N_FILE)
-	i18n = make(gt.Strings)
 	if err != nil {
 		if os.IsNotExist(err) {
-			err = nil
-			return
+			return make(gt.Strings), nil
 		}
-		i18n = nil
-		return
+		return nil, err
+	}
+	i18n = make(gt.Strings)
+	if err = yaml.Unmarshal(data, &i18n); err != nil {
+		return nil, err
 	}
-	err = yaml.Unmarshal(data, &i18n)
 	for k, v := range i18n {
+		if v == nil {
+			v = make(map[string]string)
+			i18n[k] = v
+		}
 		if _, ok := v[mainlang]; !ok {
 			v[mainlang] = k
 		}
 	}
-	return
+	return i18n, nil
 }
 
 /*
diff --git a/newi18n_test.go b/newi18n_test.go
new file mode 100644
index 0000000..539901d
--- /dev/null
+++ b/newi18n_test.go
@@ -0,0 +1,52 @@
+package zas
+
+import (
+	"os"
+	"testing"
+)
+
+// B4: NewI18n must not panic on an entry with no translations, and must
+// check the yaml.Unmarshal error before the backfill loop runs.
+
+func TestNewI18nNoFile(t *testing.T) {
+	t.Chdir(t.TempDir())
+	i18n, err := NewI18n("en")
+	if err != nil {
+		t.Fatalf("NewI18n() error = %v, want nil", err)
+	}
+	if len(i18n) != 0 {
+		t.Fatalf("NewI18n() = %v, want empty", i18n)
+	}
+}
+
+func TestNewI18nNilMapEntry(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+	if err := os.MkdirAll(ZAS_DIR, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(ZAS_I18N_FILE, []byte("Some key:\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	i18n, err := NewI18n("en")
+	if err != nil {
+		t.Fatalf("NewI18n() error = %v, want nil", err)
+	}
+	if got := i18n["Some key"]["en"]; got != "Some key" {
+		t.Fatalf("i18n[%q][%q] = %q, want %q", "Some key", "en", got, "Some key")
+	}
+}
+
+func TestNewI18nMalformedYAML(t *testing.T) {
+	dir := t.TempDir()
+	t.Chdir(dir)
+	if err := os.MkdirAll(ZAS_DIR, 0o755); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(ZAS_I18N_FILE, []byte("not: valid: yaml: [\n"), 0o644); err != nil {
+		t.Fatal(err)
+	}
+	if _, err := NewI18n("en"); err == nil {
+		t.Fatal("NewI18n() with malformed YAML: want error, got nil")
+	}
+}