"楔形文字的" can be translated as "cuneiform" when referring to something related to cuneiform script (e.g., "cuneiform inscriptions" 楔形文字铭文) or as an adjective "cuneiform-" (e.g., "cuneiform tablet" 楔形文字泥板). If used as a standalone phrase in a context like "楔形文字的特点" (the characteristics of cuneiform), you might say "the features of cuneiform..." or similar constructions.