diff --git a/src/de/hsmannheim/informatik/name/domain/starwars/C3PO.java b/src/de/hsmannheim/informatik/name/domain/starwars/C3PO.java
index 3e31b53..2889848 100644
--- a/src/de/hsmannheim/informatik/name/domain/starwars/C3PO.java
+++ b/src/de/hsmannheim/informatik/name/domain/starwars/C3PO.java
@@ -3,9 +3,8 @@ package de.hsmannheim.informatik.name.domain.starwars;
 import de.hsmannheim.informatik.name.domain.exceptions.RobotException;
 
 public class C3PO extends StarWarsRobot {
-    @Override
-    public String speak(int[] zahlen) throws RobotException {
-        return null;
+    public C3PO() {
+        super(';');
     }
 
     @Override
@@ -13,8 +12,8 @@ public class C3PO extends StarWarsRobot {
         int[] arrToSort = zahlen.clone();
         for (int i = 1; i < arrToSort.length; i++) {
             for (int j = i; j > 0; j--) {
-                if (arrToSort[j-1] > arrToSort[j]) {
-                    swap(arrToSort, j, j-1);
+                if (arrToSort[j - 1] > arrToSort[j]) {
+                    swap(arrToSort, j, j - 1);
                 }
             }
         }
diff --git a/src/de/hsmannheim/informatik/name/domain/starwars/R2D2.java b/src/de/hsmannheim/informatik/name/domain/starwars/R2D2.java
index bc12cc4..ac84cd6 100644
--- a/src/de/hsmannheim/informatik/name/domain/starwars/R2D2.java
+++ b/src/de/hsmannheim/informatik/name/domain/starwars/R2D2.java
@@ -3,9 +3,8 @@ package de.hsmannheim.informatik.name.domain.starwars;
 import de.hsmannheim.informatik.name.domain.exceptions.RobotException;
 
 public class R2D2 extends StarWarsRobot {
-    @Override
-    public String speak(int[] zahlen) throws RobotException {
-        return null;
+    public R2D2() {
+        super(',');
     }
 
     @Override
diff --git a/src/de/hsmannheim/informatik/name/domain/starwars/StarWarsRobot.java b/src/de/hsmannheim/informatik/name/domain/starwars/StarWarsRobot.java
index 959ba2f..bedb7c3 100644
--- a/src/de/hsmannheim/informatik/name/domain/starwars/StarWarsRobot.java
+++ b/src/de/hsmannheim/informatik/name/domain/starwars/StarWarsRobot.java
@@ -1,11 +1,17 @@
 package de.hsmannheim.informatik.name.domain.starwars;
 
-import de.hsmannheim.informatik.name.domain.robot_interfaces.Robot;
 import de.hsmannheim.informatik.name.domain.exceptions.RobotException;
+import de.hsmannheim.informatik.name.domain.robot_interfaces.Robot;
 
 
 public abstract class StarWarsRobot implements Robot {
 
+    private final char SEPARATOR;
+
+    protected StarWarsRobot(char separator) {
+        SEPARATOR = separator;
+    }
+
     @Override
     public int getId() {
         return 0;
@@ -32,9 +38,19 @@ public abstract class StarWarsRobot implements Robot {
     }
 
     @Override
-    public abstract String speak(int[] zahlen) throws RobotException;
+    public String speak(int[] zahlen) throws RobotException {
+        StringBuilder sb = new StringBuilder();
+        //Loops through every element of zahlen[]
+        for (int i = 0; i < zahlen.length; i++) {
+            sb.append(zahlen[i]);
+            //if current number is not the last number add a separator
+            if (i != zahlen.length - 1) {
+                sb.append(SEPARATOR).append(" ");
+            }
+        }
+        return sb.toString();
+    }
 
-    @Override
     public abstract int[] think(int[] zahlen) throws RobotException;
 
     protected static void swap(int[] arr, int a, int b) {
diff --git a/tests/R2D2SpeakTest.java b/tests/R2D2SpeakTest.java
new file mode 100644
index 0000000..f7a2586
--- /dev/null
+++ b/tests/R2D2SpeakTest.java
@@ -0,0 +1,36 @@
+import de.hsmannheim.informatik.name.domain.exceptions.RobotException;
+import de.hsmannheim.informatik.name.domain.starwars.R2D2;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+class R2D2SpeakTest {
+
+    private final R2D2 r2d2 = new R2D2();
+
+    @Test
+    void speakTestStandard() throws RobotException {
+        assertEquals("1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12", r2d2.speak(new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}));
+    }
+
+    @Test
+    void speakTestEmpty() throws RobotException {
+        assertEquals("", r2d2.speak(new int[]{}));
+    }
+
+    @Test
+    void speakTestZeros() throws RobotException {
+        assertEquals("0, 0, 0, 0", r2d2.speak(new int[4]));
+    }
+
+    @Test
+    void speakTestOneElement() throws RobotException {
+        assertEquals("1", r2d2.speak(new int[]{1}));
+    }
+
+    @Test
+    void speakTestUnitElements() throws RobotException {
+        assertEquals("-1, 0, 1", r2d2.speak(new int[]{-1, 0, 1}));
+    }
+}
\ No newline at end of file
diff --git a/tests/R2D2Test.java b/tests/R2D2Test.java
deleted file mode 100644
index fa6e7ba..0000000
--- a/tests/R2D2Test.java
+++ /dev/null
@@ -1,12 +0,0 @@
-import static org.junit.jupiter.api.Assertions.*;
-
-class R2D2Test {
-
-    @org.junit.jupiter.api.Test
-    void speak() {
-    }
-
-    @org.junit.jupiter.api.Test
-    void think() {
-    }
-}
\ No newline at end of file
diff --git a/tests/R2D2ThinkTest.java b/tests/R2D2ThinkTest.java
new file mode 100644
index 0000000..bc99362
--- /dev/null
+++ b/tests/R2D2ThinkTest.java
@@ -0,0 +1,4 @@
+public class R2D2ThinkTest {
+
+
+}