The ornamental design for a front of a check speller, as shown and described.
FIG. 1 is a front perspective view of a first embodiment of a front of a check speller showing my new design; and,
FIG. 2 is a front perspective view of a second embodiment thereof.
The broken line showing of the check in FIG. 1 and the calendar and the pages in FIG. 2 is for illustrative purposes only and forms no part of the claimed design.