Toward the end of the first year, infants use patterns of rising and falling that resemble the sounds of adult speech.

"Toward the end of the first year, infants use patterns of rising and falling intonation that resemble the sounds of adult speech."

Intonation is the way the pitch of the voice goes up and down as you speak.

Reproducing adult intonations is one of the ways young children pick up the speech patterns in the language which is spoken at home, even before they know how to formulate sentences. It is the result of the imprint of their parents' speech on their memory. Therefore, when the child then prattles using this intonation, it may sound like they are babbling in their parents' language.

b) the planets year length would be longer

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answer; knowledge,reason,and judgement;