With Love... with sign language?

[lalois.livejournal.com]

Hello!
Sorry, I'm not even sure whether this post/question might be OT here.
I finished watching Takizawa Kabuki ZERO yesterday (awesome *O*), and while the With Love performance aired, and I noticed they made signs during the choreography. Is it just my impression or did they really "talked" in the Japanese sign language while singing throughout that part of the performance?
Here a screencap of the part I'm referring to:


If this was a well-known info, I'm sorry I didn't know. I'm new into the fandom so that's why my question arrives now XD
Thanks in advance to anyone who might help and let me now!