diff --git a/pint/delegates/formatter/_format_helpers.py b/pint/delegates/formatter/_format_helpers.py
index 5f36b39d0..1df07e03d 100644
--- a/pint/delegates/formatter/_format_helpers.py
+++ b/pint/delegates/formatter/_format_helpers.py
@@ -212,7 +212,7 @@ def short_form(
     registry: UnitRegistry,
 ) -> Iterable[tuple[str, T]]:
     """Replace each unit by its short form."""
-    return map_keys(registry.get_symbol, units)
+    return map_keys(registry._get_symbol, units)
 
 
 def localized_form(