So a single-target version of silence with no concentration requirement and affects the creature for 1 minute no matter where they move? I like it.  Lichs are decent at Wisdom saves, but not amazing for their level, but it's a good way to force a Lich to use it's Legendary Resistance (imagine using Legendary Resistance on a 2nd-level spell).  It does have a suggestion or hypnotic pattern-like effect of locking one creature out of the fight temporarily so you can deal with other enemies, but only works on spellcasters and doesn't require concentration.  You cast it on the enemy spellcaster and if you succeed you are free to do whatever you want with your other concentration slot.  

A notable downside of this spell is stealth, since it will make a creature scream loudly (alerting other enemies in the area since they will here the voice of one of their comrades and believe one of their comrades is in danger, so they will want to investigate the source of the sound).  

you just copied someone else's spell