diff --git a/src/engine/registry.ts b/src/engine/registry.ts
index 194cc86..dfe20b2 100644
--- a/src/engine/registry.ts
+++ b/src/engine/registry.ts
@@ -88,7 +88,7 @@ export class Registry {
     const list = this.byFirst.get(key);
     if (list) {
       // first registration of an identical phrase wins (core vocab is added first)
-      if (list.some((e) => e.caseSensitive === caseSensitive && (caseSensitive ? e.lexemes.join(" ") === lexemes.join(" ") : e.lower.join(" ") === entry.lower.join(" ")))) {
+      if (list.some((e) => e.caseSensitive === caseSensitive && e.lexemes.length === lexemes.length && (caseSensitive ? e.lexemes.every((l, i) => l === lexemes[i]) : e.lower.every((l, i) => l === entry.lower[i])))) {
         return;
       }
       list.push(entry);