Emotional Weight

Usually insults only weigh someone down emotionally.  Bards, however, don't heed such rules.  This spell has you chug a vial of tears and choose your target.  With a well crafted insult (probably to their mother) you force your target to make a CHA saving throw, trying to beat your CHA stat number.  If the target fails the saving throw, they lose 10 ft of movement speed for two turns, as well as disadvantage on all acrobatics and athletics saves for the same duration.  This spell fails if the target cannot understand your language.