diff --git a/lambda/Makefile b/lambda/Makefile
index ef23aad..69df61a 100644
--- a/lambda/Makefile
+++ b/lambda/Makefile
@@ -12,6 +12,9 @@
 ## This is where your main() routine lives 
 MAIN = lambda.c
 
+## en: 0 (default), de: 1
+LANG = 0
+
 ## If you've split your program into multiple .c / .h files, 
 ## include the additional source (in same directory) here 
 LOCAL_SOURCE = usart.c interrupts.c adc.c sensors.c integers.c lcdroutines.c \
@@ -48,7 +51,8 @@
 AVRDUDE = avrdude
 
 ## Compilation options, type man avr-gcc if you're curious.
-CFLAGS = -mmcu=$(MCU) -DF_CPU=$(F_CPU)UL -DBAUD=$(BAUD) -Os -I. -I$(EXTRA_SOURCE_DIR)
+CFLAGS = -mmcu=$(MCU) -DF_CPU=$(F_CPU)UL -DBAUD=$(BAUD) -DLANG=$(LANG) 
+CFLAGS += -Os -I. -I$(EXTRA_SOURCE_DIR)
 CFLAGS += -funsigned-char -funsigned-bitfields -fpack-struct -fshort-enums 
 CFLAGS += -Wall -Wstrict-prototypes
 CFLAGS += -g -ggdb
diff --git a/lambda/messages.h b/lambda/messages.h
index d11056d..fe86ce7 100644
--- a/lambda/messages.h
+++ b/lambda/messages.h
@@ -8,22 +8,50 @@
 #ifndef MESSAGES_H_
 #define MESSAGES_H_
 
-/* lambda.c */
-#define MSG_WELCOME "     Hello!     "
+#ifndef LANG
+	#define LANG 0
+#endif
 
-/* sensors.c */
-#define MSG_LEAN "Lean "
-#define MSG_OKAY "Okay "
-#define MSG_IDEAL "Ideal"
-#define MSG_RICH "Rich!"
+#if LANG == 0
 
-/* rules.c */
-#define MSG_AIRGATE_50_0 "Air gate 50%"
-#define MSG_AIRGATE_25_0 "Air gate 25%"
-#define MSG_AIRGATE_CLOSE_0 "Close air gate"
-#define MSG_AIRGATE_CLOSE_1 "Turn off heating"
-#define MSG_TOO_RICH_0 "Too rich, open"
-#define MSG_TOO_RICH_1 "air gate!"
-#define MSG_FIRE_OUT_0 "Fire out?"
+	/* lambda.c */
+	#define MSG_WELCOME "     Hello!     "
+
+	/* sensors.c */
+	#define MSG_LEAN "Lean "
+	#define MSG_OKAY "Okay "
+	#define MSG_IDEAL "Ideal"
+	#define MSG_RICH "Rich!"
+
+	/* rules.c */
+	#define MSG_AIRGATE_50_0 "Air gate 50%"
+	#define MSG_AIRGATE_25_0 "Air gate 25%"
+	#define MSG_AIRGATE_CLOSE_0 "Close air gate"
+	#define MSG_AIRGATE_CLOSE_1 "Turn off heating"
+	#define MSG_TOO_RICH_0 "Too rich, open"
+	#define MSG_TOO_RICH_1 "air gate"
+	#define MSG_FIRE_OUT_0 "Fire out?"
+
+#elif LANG == 1
+
+	/* lambda.c */
+	#define MSG_WELCOME "     Hallo!     "
+
+	/* sensors.c */
+	#define MSG_LEAN "Mager"
+	#define MSG_OKAY "Okay "
+	#define MSG_IDEAL "Ideal"
+	#define MSG_RICH "Fett!"
+
+	/* rules.c */
+	#define MSG_AIRGATE_50_0 "Luftschieber 50%"
+	#define MSG_AIRGATE_25_0 "Luftschieber 25%"
+	#define MSG_AIRGATE_CLOSE_0 "Luftschieber zu"
+	#define MSG_AIRGATE_CLOSE_1 "Heiz. abschalten"
+	#define MSG_TOO_RICH_0 "Zu fett, Luft-"
+	#define MSG_TOO_RICH_1 "schieber oeffnen"
+	#define MSG_FIRE_OUT_0 "Feuer aus?"
+
+#endif
 
 #endif /* MESSAGES_H_ */