diff --git a/src/altk/effcomm/tradeoff.py b/src/altk/effcomm/tradeoff.py
index 3002c1eb..2641bc1f 100644
--- a/src/altk/effcomm/tradeoff.py
+++ b/src/altk/effcomm/tradeoff.py
@@ -205,7 +205,7 @@ def tradeoff(
             lang.data[prop] = properties[prop](lang)
         points.append((lang.data[x], lang.data[y]))
 
-    dominating_languages = pareto_optimal_languages(languages, x, y, unique=True)
+    dominating_languages = pareto_optimal_languages(languages, objectives=[properties[x], properties[y]], unique=True)
     dominant_points = [(lang.data[x], lang.data[y]) for lang in dominating_languages]
 
     if frontier is not None: