noun
baby talk; baby language; babbling
Refers to the simplified, repetitive, and often onomatopoeic speech used by or toward babies and young children. Can also describe the babbling stage of language development.
赤ちゃん言葉で話しかけると、赤ちゃんが喜ぶ。
When you talk in baby talk, the baby gets happy.
「わんわん
"Wanwan" (doggy) and "buubuu" (vroom-vroom) are examples of baby talk.