The ornamental design for a skateboottongue, as shown and described.
FIG. 1 is a perspective view taken from a front, right side of a skate boot tongue according to my design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a perspective view taken from a front, left side thereof;
FIG. 4 is a right side elevation view thereof;
FIG. 5 is a left side elevation view thereof; and,
FIG. 6 is a perspective view taken from a front, right side thereof shown on a skate boot shown in dotted lines.
Throughout the Figures, where shown: (i) the broken lines showing additional structure of the skate boot tongue and the skate boot on which it is shown are for illustrative purposes only and form no part of the claimed design; (ii) the dotted/dashed lines adjacent shaded surfaces represent unclaimed boundaries of the claimed design; and (iii) the unshaded surfaces do not form part of the claimed design. Portions of the skate boot tongue not shown in the Figures do not form part of the claimed design.