The Kansas City Chiefs tight end opened up on his relationship with the pop icon in an interview with the Wall Street Journal this week ... where he detailed how he's personally growing from their one-on-one time together.

"I've never been a man of words," Kelce said. "Being around her, seeing how smart Taylor is, has been f***ing mind-blowing. I'm learning every day."

Kelce also praised Swift's ability to turn her own experiences into words ... specifically pointing out his love for a line in her hit song, "Blank Space" -- when she sings, "I could make a bad guy good for the weekend."

Kelce -- who referred to Swift as "hilarious" and a "genius" -- added the two are on the same page with their views ... especially when it comes to family.

"Everybody knows I'm a family guy. Her team is her family. Her family does a lot of stuff in terms of the tour, the marketing, being around, so I think she has a lot of those values as well, which is right up my alley."

As for how they first linked up, the two-time Super Bowl champion said someone in Taylor's circle played Cupid after he publicly shot his shot on his podcast ... and eventually, Taylor reached out directly.

Another interesting point -- Travis claims his mother, Donna, is upset with herself to this day about how she downplayed meeting Taylor for the first time during her appearance on the "Today" show ... when she famously said it was just "okay."

Kelce says his mom was just trying to play it cool ... but he reassured her she handled the question perfectly.