code: function getSubstitutions( pos ) {
  	var substitutions;
  	switch ( pos ) {
  	case 'n':
  		substitutions = _.clone( MORPHY_SUBSTITUTIONS.NOUN );
  	break;
  	case 'v':
  		substitutions = _.clone( MORPHY_SUBSTITUTIONS.VERB );
  	break;
  	case 'a':
  		substitutions = _.clone( MORPHY_SUBSTITUTIONS.ADJECTIVE );
  	break;
  	default:
  		substitutions = [];
  	}
  	return substitutions;
  }
docs: GET SUBSTITUTIONS // 
  Return a copy of the respective substitutions array.
  
  @param {string} pos - part of speech
  @returns {Array} substitutions instance