diff --git a/src/machineLearning/trainingData.h b/src/machineLearning/trainingData.h
index 614f967c775589fe1e559fd61173bee065386df2..e9c12eb26fd0a6b21b9383d11990df04c6c8df9e 100644
--- a/src/machineLearning/trainingData.h
+++ b/src/machineLearning/trainingData.h
@@ -37,12 +37,22 @@ namespace rapidmix {
         struct phrase {
             uint32_t uniqueId;
             std::string label; //TODO: Need to work this with templates
-            std::vector<std::string> columnNames;
+            std::vector<std::string> columnNames; //equal to the number of inputs
             std::vector<element> elements;
+            
+            void addElement (const std::vector<double> &input, const std::vector<double> &output)
+            {
+                
+            }
         };
         
         std::vector<phrase> trainingSet;
         
+        //TODO: Deleting phrases (last or by label)
+        //Design ideas to make phrase building stateless:
+        //phrase& createNewPhrase();
+        //addElementToPhrase();
+        
         /** Create a new phrase that can be recorded into. Returns phrase id */
         uint32_t startRecording(); //FIXME: this should go away. -MZ
         
@@ -71,7 +81,6 @@ namespace rapidmix {
         std::vector<std::string> getColumnNames();
         void setColumnNames(const std::vector<std::string> &columnNames);
         
-        
         /** Get a JSON representation of the data set in the form of a styled string */
         std::string getJSON();
         /** Write a JSON version of the training set to specified file path */