Jessa (Duggar) Seewald Shares Smiley Video of Baby Spurgeon

Spurgeon Elliot Seewald just turned 4 months old

Photo: Jessa Seewald/Instagram

Jessa (Duggar) Seewald is spending time bonding with her baby Spurgeon.

“What have you been learning?” Jessa, 23, coos in an Instagram video posted late Wednesday as her son smiles and babbles – or as the new mom proudly put it, “showing off all his new vocabulary skills.”

In this week’s issue of PEOPLE, Jessa opens up about the parenting advice she got from mom Michelle Duggar.

“She has raised just about every personality type, so I really enjoy learning from her,” Jessa says. “But my baby is really still young, so most of my questions these days are about breastfeeding and when to change diaper sizes.”

The Jill and Jessa: Counting On reality star and husband Ben Seewald commemorated Spurgeon’s 4-month birthday on with a trip to an ice cream shop.

And her sister Jill (Duggar) Dillard wished husband Derick Dillard a happy 27th birthday with a kissing selfie Wednesday.

• For more on the Duggars’ lives these days, pick up this week’s issue of PEOPLE, on newsstands Friday

There’s another occasion to celebrate now, too: Jill and Jessa’s brother Josh Duggar‘s return from rehab.

PEOPLE has confirmed that Josh, 28, is back home in Arkansas after a seven-month stay at the faith-based Reformers Unanimous in Rockford, Illinois, where he checked in last summer following his confession to harboring a porn addiction and cheating on his wife Anna Duggar.

Counting On premieres Tuesday at 9 p.m. ET on TLC.