diff --git a/TODO.md b/TODO.md
index bb779ed..5e3b857 100644
--- a/TODO.md
+++ b/TODO.md
@@ -2,6 +2,10 @@
 
 ## Completed
 
+- [x] Language form improvements
+  - [x] Add Néerlandais as default language option (schema + migration 017)
+  - [x] Make `language_autre` required only when no Langue du TFE checkbox is checked (JS in form.php, PHP server-side default)
+
 - [x] Merge banner images into cover images
   - [x] Migration 016: copy `storage/banners/*` → `storage/covers/`, insert `thesis_files` cover records, clear `banner_path`, remove banners dir
   - [x] Remove banner fieldset from edit form (`form.php`)
diff --git a/app/migrations/applied/017_add_dutch_language.sql b/app/migrations/applied/017_add_dutch_language.sql
new file mode 100644
index 0000000..0042206
--- /dev/null
+++ b/app/migrations/applied/017_add_dutch_language.sql
@@ -0,0 +1 @@
+INSERT OR IGNORE INTO languages (name) VALUES ('Néerlandais');
diff --git a/app/storage/schema.sql b/app/storage/schema.sql
index 2ff8ad0..b418758 100644
--- a/app/storage/schema.sql
+++ b/app/storage/schema.sql
@@ -90,7 +90,8 @@ CREATE TABLE IF NOT EXISTS languages (
 
 INSERT OR IGNORE INTO languages (name) VALUES
     ('Français'),
-    ('Anglais');
+    ('Anglais'),
+    ('Néerlandais');
 
 -- Format types (can select multiple)
 CREATE TABLE IF NOT EXISTS format_types (
diff --git a/app/templates/partials/form/form.php b/app/templates/partials/form/form.php
index 83bdb8c..689fa58 100644
--- a/app/templates/partials/form/form.php
+++ b/app/templates/partials/form/form.php
@@ -165,7 +165,7 @@ $checkedFormatsForSiteWeb = $checkedFormatsForSiteWeb ?? [];
 <?php endif; ?>
 
         <!-- ═══════════════════ Langue(s) ═══════════════════ -->
-        <fieldset>
+        <fieldset id="languages-fieldset">
             <legend>Langue(s)</legend>
             <?php
             $name = "languages";
@@ -179,11 +179,44 @@ $checkedFormatsForSiteWeb = $checkedFormatsForSiteWeb ?? [];
             $name = "language_autre";
             $label = "Autre(s) langue(s) :";
             $value = $oldFn("language_autre");
+            $required = empty($formData["languages"]);
             $hint =
                 "Si votre TFE contient une langue absente de la liste, précisez-la ici.";
             include APP_ROOT . "/templates/partials/form/text-field.php";
             ?>
         </fieldset>
+        <script>
+        (function () {
+            var fs = document.getElementById('languages-fieldset');
+            if (!fs) return;
+            var autreInput = fs.querySelector('input[name="language_autre"]');
+            if (!autreInput) return;
+            var autreLabel = fs.querySelector('label[for="language_autre"]');
+            function update() {
+                var anyChecked = fs.querySelectorAll('input[name="languages[]"]').length > 0
+                    ? Array.from(fs.querySelectorAll('input[name="languages[]"]')).some(function(cb){ return cb.checked; })
+                    : false;
+                autreInput.required = !anyChecked;
+                if (autreLabel) {
+                    var star = autreLabel.querySelector('.asterisk');
+                    if (!anyChecked && !star) {
+                        var s = document.createElement('span');
+                        s.className = 'asterisk';
+                        s.textContent = '*';
+                        autreLabel.appendChild(document.createTextNode(' '));
+                        autreLabel.appendChild(s);
+                    } else if (anyChecked && star) {
+                        star.previousSibling && star.previousSibling.nodeType === 3 && star.previousSibling.remove();
+                        star.remove();
+                    }
+                }
+            }
+            fs.addEventListener('change', function(e) {
+                if (e.target && e.target.name === 'languages[]') update();
+            });
+            update();
+        })();
+        </script>
 
         <!-- ═══════════════════ Mots-clés ═══════════════════ -->
         <fieldset>