13. An apparatus that can be used to specify a subset of data, comprising: a communication interface; a storage device; and one or more processors in communication with the storage device and the communication interface, the one or more processors receive a selection of a command and display a natural language expression that includes the command and at least a first changeable field embedded in the displayed natural language expression in response to receiving the selection of the command, the one or more processors receive a indication of first data for the first changeable embedded field from a direct interaction with the displayed natural language expression and modify the natural language expression in response to the first data and display the modified natural language expression, the one or more processors display an add field indicator, the one or more processors receive a selection of the add field indicator from a direct interaction with the displayed natural language expression and add a second changeable field embedded in the natural language expression in response to the selection of the add field indicator and display the natural language expression with the second changeable field embedded in the displayed natural language expression, the one or more processors receive a indication of second data for the second changeable embedded field from a direct interaction with the displayed natural language expression and modify the natural language expression in response to the second data and display the modified natural language expression.
13. An apparatus that can be used to specify a subset of data, comprising: a communication interface; a storage device; and one or more processors in communication with the storage device and the communication interface, the one or more processors receive a selection of a command and display a natural language expression that includes the command and at least a first changeable field embedded in the displayed natural language expression in response to receiving the selection of the command, the one or more processors receive a indication of first data for the first changeable embedded field from a direct interaction with the displayed natural language expression and modify the natural language expression in response to the first data and display the modified natural language expression, the one or more processors display an add field indicator, the one or more processors receive a selection of the add field indicator from a direct interaction with the displayed natural language expression and add a second changeable field embedded in the natural language expression in response to the selection of the add field indicator and display the natural language expression with the second changeable field embedded in the displayed natural language expression, the one or more processors receive a indication of second data for the second changeable embedded field from a direct interaction with the displayed natural language expression and modify the natural language expression in response to the second data and display the modified natural language expression. 18. The apparatus claim 13 , wherein: the one or more processors access a group of data; the one or more processors identify a subset of the group of data that is defined by the displayed natural language expression; and the one or more processors report the subset of the group of data.