詞匯?

1.????? infant 嬰兒，幼兒

2.????? address 向…說話

3.????? calf 幼崽，幼獸

4.????? signature 簽名，標志性的

5.????? offspring 后代，子女

Dolphin moms use baby talk to call to their young, recordings show

You know instantly when someone is speaking to an infant or small child. It turns out that dolphin mothers also use a kind of high-pitched baby talk. A recent study found that female bottlenose dolphins change their tone when addressing their calves. Researchers recorded the signature whistles of 19 mother dolphins in Florida, when accompanied by their young offspring and when swimming alone or with other adults.