Some Clarity In The Kalir

וישמע הכנעני מלך ערד ישב הנגב *                זכור יושב הנגב בלי על כערד כסות ולשון שנה פיוט פ' זכור Rashi explains that הכנעני was actually עמלק who was ישב הנגב but disguised himself, by speaking in the language of  כנען to confuse the Yidden when they will Daven to Hashem  to save them from the enemy כנען instead of עמלק However, since they  wore Amaleiki clothing the Yidden realized something doesn't make sense and Davend  without mentioning any name of the enemy. The Kalir in the Piyut of Shabbos Parshas Zachor writes זכור יושב הנגב בלי על כערד כסות ולשון שנה Seems that the Kalir holds that he changed both, his clothing and language.(כסות ולשון) The (מהרש"א (ר"ה ג ע"א writes we can say that the Kalir & Rashi are not arguing. The meaning of כסות ולשון שנה is that the כסות didn't match the לשון since he wore Amaleiki clothes and spoke Kanani language. (same like Rashi)   *Bamidbar 21:1