diff --git a/index.js b/index.js
index 057bfdc..b3b2078 100644
--- a/index.js
+++ b/index.js
@@ -46,8 +46,8 @@ Handlebars.registerHelper('icon', (name, fallback) =>
   }),
 )
 
-Handlebars.registerHelper('join', (arr, separator) =>
-  arr.join(typeof separator === 'string' ? separator : ', '),
+Handlebars.registerHelper('join', arr =>
+  Intl.ListFormat ? new Intl.ListFormat('en').format(arr) : arr.join(', '),
 )
 
 Handlebars.registerHelper('markdown', doc => micromark(doc))
diff --git a/tap-snapshots/test/render.js.test.cjs b/tap-snapshots/test/render.js.test.cjs
index 88a5ce6..1243cb0 100644
--- a/tap-snapshots/test/render.js.test.cjs
+++ b/tap-snapshots/test/render.js.test.cjs
@@ -386,7 +386,7 @@ blockquote > * + * {
                   </span>
                 </div>
                 <span>
-                    <strong>Team lead, Designer</strong>
+                    <strong>Team lead and Designer</strong>
                     at <strong>Smoogle</strong>
                 </span>
               </header>