diff --git a/src/Kaleidoscope.h b/src/Kaleidoscope.h
index f366a8a4..d0d39c87 100644
--- a/src/Kaleidoscope.h
+++ b/src/Kaleidoscope.h
@@ -44,12 +44,41 @@ void setup();
 
 #include "kaleidoscope/hid.h"
 
+
+// Note: The CONVERT_TO_KEY macro can be redefined to use different
+//       host_keymap-keymaps on different layers (see key_defs.h for its
+//       default definition.
+
+#define CONVERT_AND_CHECK_KEY(KEY)                                             \
+   (                                                                           \
+   (                                                                           \
+      struct {                                                                 \
+         static_assert(CONVERT_TO_KEY(KEY) != kaleidoscope::bad_keymap_key,    \
+                       "Bad key definition: \'" #KEY "\'");                    \
+      }                                                                        \
+   ){},                                                                        \
+   CONVERT_TO_KEY(KEY)                                                         \
+   )
+
 #ifdef PER_KEY_DATA_STACKED
-#define KEYMAP_STACKED(...) { PER_KEY_DATA_STACKED(XXX, __VA_ARGS__) }
+#define KEYMAP_STACKED(...)                                                    \
+   {                                                                           \
+      MAP_LIST(                                                                \
+         CONVERT_AND_CHECK_KEY,                                                \
+         PER_KEY_DATA_STACKED(XXX, __VA_ARGS__)                                \
+      )                                                                        \
+   }
+
 #endif
 
 #ifdef PER_KEY_DATA
-#define KEYMAP(...) { PER_KEY_DATA(XXX, __VA_ARGS__) }
+#define KEYMAP(...)                                                            \
+   {                                                                           \
+      MAP_LIST(                                                                \
+         CONVERT_AND_CHECK_KEY,                                                \
+         PER_KEY_DATA(XXX, __VA_ARGS__)                                        \
+      )                                                                        \
+   }
 #endif
 
 #include "kaleidoscope/KeyAddr.h"
diff --git a/src/kaleidoscope/key_defs.h b/src/kaleidoscope/key_defs.h
index 31f9acae..d3adee7e 100644
--- a/src/kaleidoscope/key_defs.h
+++ b/src/kaleidoscope/key_defs.h
@@ -197,6 +197,13 @@ constexpr Key addFlags(Key k, uint8_t add_flags) {
 
 } // namespace kaleidoscope
 
+// Redefine this macro to enable using alternative char-string to Key
+// conversions per layer. This is, howerver, only necessary in rare cases
+// (e.g. to use individual host_keymap language maps on
+// different layers, see kaleidoscope/host_keymap/host_keymap.h for an example).
+//
+#define CONVERT_TO_KEY(INPUT) kaleidoscope::convertToKey(INPUT)
+
 // For compatibility reasons make the Key class also available
 // in global namespace.
 //
@@ -213,11 +220,11 @@ typedef kaleidoscope::Key Key_;
 #define SYNTHETIC         B01000000
 #define RESERVED          B10000000
 
-#define LCTRL(k)  Key(k.getKeyCode(), k.getFlags() | CTRL_HELD)
-#define LALT(k)   Key(k.getKeyCode(), k.getFlags() | LALT_HELD)
-#define RALT(k)   Key(k.getKeyCode(), k.getFlags() | RALT_HELD)
-#define LSHIFT(k) Key(k.getKeyCode(), k.getFlags() | SHIFT_HELD)
-#define LGUI(k)   Key(k.getKeyCode(), k.getFlags() | GUI_HELD)
+#define LCTRL(k)  kaleidoscope::addFlags(CONVERT_TO_KEY(k), CTRL_HELD)
+#define LALT(k)   kaleidoscope::addFlags(CONVERT_TO_KEY(k), LALT_HELD)
+#define RALT(k)   kaleidoscope::addFlags(CONVERT_TO_KEY(k), RALT_HELD)
+#define LSHIFT(k) kaleidoscope::addFlags(CONVERT_TO_KEY(k), SHIFT_HELD)
+#define LGUI(k)   kaleidoscope::addFlags(CONVERT_TO_KEY(k), GUI_HELD)
 
 // we assert that synthetic keys can never have keys held, so we reuse the _HELD bits
 #define IS_SYSCTL                  B00000001