diff --git a/runtime/ftplugin/dot.lua b/runtime/ftplugin/dot.lua
new file mode 100644
index 0000000000..89ab42ef54
--- /dev/null
+++ b/runtime/ftplugin/dot.lua
@@ -0,0 +1,3 @@
+vim.bo.commentstring = '// %s'
+
+vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '') .. '\n setl commentstring<'
diff --git a/runtime/ftplugin/faust.lua b/runtime/ftplugin/faust.lua
new file mode 100644
index 0000000000..89ab42ef54
--- /dev/null
+++ b/runtime/ftplugin/faust.lua
@@ -0,0 +1,3 @@
+vim.bo.commentstring = '// %s'
+
+vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '') .. '\n setl commentstring<'
diff --git a/runtime/ftplugin/stata.lua b/runtime/ftplugin/stata.lua
new file mode 100644
index 0000000000..89ab42ef54
--- /dev/null
+++ b/runtime/ftplugin/stata.lua
@@ -0,0 +1,3 @@
+vim.bo.commentstring = '// %s'
+
+vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '') .. '\n setl commentstring<'
diff --git a/runtime/ftplugin/supercollider.lua b/runtime/ftplugin/supercollider.lua
new file mode 100644
index 0000000000..89ab42ef54
--- /dev/null
+++ b/runtime/ftplugin/supercollider.lua
@@ -0,0 +1,3 @@
+vim.bo.commentstring = '// %s'
+
+vim.b.undo_ftplugin = (vim.b.undo_ftplugin or '') .. '\n setl commentstring<'
diff --git a/runtime/ftplugin/swift.lua b/runtime/ftplugin/swift.lua
new file mode 100644
index 0000000000..0f90644f11
--- /dev/null
+++ b/runtime/ftplugin/swift.lua
@@ -0,0 +1,3 @@
+vim.bo.commentstring = '// %s'
+
+vim.b.undo_ftplugin = vim.b.undo_ftplugin .. ' | setl commentstring<'