I respectfully disagree with the other answers. There is an important difference between "to be known" and "to know." "To be known for X" means "to be famous for X." "To know X" or "to know to do X" means "to know how to do X." Here, "... the older generations were not known for the (sic) [their] tender talk" means that they were not famous for their loving words. [It was not common for them to use loving words.]

Where would you put it?

Hi! Coco is right. Let me add... You may change TENDER into GENTLE: [That’s an exaggerated joke BUT of course the older generations DID NOT KNOW how to be GENTLE in their talk.] [That’s an exaggerated joke BUT of course the older generations DID NOT KNOW how to be GENTLE with their WORDS.] [That’s an exaggerated joke BUT of course the older generations were not known for their GENTLE WORDS.] Have a great day!