public void learnSymbol(int symbol){
  mStartInsertionNode=insertSymbol(mStartInsertionNode,symbol);
}

public void learnSymbol ( int symbol ) { mStartInsertionNode = insertSymbol ( mStartInsertionNode , symbol ) ; }
updates the trie to include the specified symbol . when the symbol is inserted into the trie the node that was inserted at the highest level is tracked . this enables us to track the n most recent symbols inserted into the trie , which hence give us the user context .
