why do people insist on talking to babies in such?

it's called 'motherese.'

what's more annoying is the tongue clacking my boyfriend's mother does every time she sees my son. click clack cluck cluck click cluck clack.

I used to take linguistics classes at school. wiki is right on with their article:

Baby talk, also referred to as caretaker speech, infant-directed talk (IDT) or child-directed speech (CDS)[1][2][3][4] and informally as "motherese", "parentese", or "mommy talk"), is a nonstandard form of speech used by adults in talking to toddlers and infants. It is usually delivered with a "cooing" pattern of intonation different from that of normal adult speech: high in pitch, with many glissando variations that are more pronounced than those of normal speech. Baby talk is also characterized by the shortening and simplifying of words.

Use with infants

Baby talk is more effective than regular speech in getting an infant's attention. Studies have shown that infants actually prefer to listen to this type of speech.[6] Some researchers, including Rima Shore (1997), believe that baby talk is an important part of the emotional bonding process.

Colwyn Trevarthen studied babies and their mothers. He observed the communication and subtle movements between the babies and mothers. He has links to music therapy with other theorists.[7]

Aid to cognitive development

Shore and other researchers believe that baby talk contributes to mental development, as it helps teach the child the basic function and structure of language. Studies have found that responding to an infant's babble with meaningless babble aids the infant's development; while the babble has no logical meaning, the verbal interaction demonstrates to the child the bidirectional nature of speech, and the importance of verbal feedback. Some experts advise that parents should not talk to infants and young children solely in baby talk, but should integrate some normal adult speech as well. The high-pitched sound of motherese gives it special acoustic qualities which may appeal to the infant (Goodluck 1991). Motherese may aid a child in the acquisition and/or comprehension of language-particular rules which are otherwise unpredictable, when utilizing principles of universal grammar (Goodluck 1991). Some[who?] feel that parents should refer to the child and others by their names only (no pronouns, e.g., he, I, or you), to avoid confusing infants who have yet to form an identity independent from their parents.

http://en.wikipedia.org/wiki/Baby_talk

yes! its actually called mother-ese. (like portugese, japanese, chinese etc)

When a baby is small, it learns everything to do with language from the people around him. Motherese is inbuilt to humans (women and men) which is why so many people do it accidentally.

Its not scientific, its just natural!

When people talk so slowly, slightly higher, and clearer to a baby using simple language, this helps the baby to learn about language more quickly than if the people around him speak like they do to adults. Children growing up in this environment can end up with speech problems due to not having enough time spent on basic language development.

When you speak slowly and clearly to a baby you are putting emphasis on the vowel sounds and basic sound patterns which make up language (even if a child is bi or multilingual!)

Motherese is actually recommended by docs, as it helps baby recognise language more easily.

Also to answer your question, yes it can make a baby be quiet too, especially if its the mummy doing the talking. It makes baby realize that mummy is speaking specifically to him or her, and this makes baby feel more secure and valued, which in turn will help him relax.

Perhaps it is annoying, however it is very valuable to babies development. Why not try it with the next baby you come across, speak normally one time, then next time speak in a slower, more highly pitched voice, and see if the baby responds different to you!

Studies have found that babies are attracted to higher pitch voices. I suppose because mothers have higher pitched voices than fathers and instincts tell them to respond to the mother better as she will take care of the baby.

As to why people do it - you can't help yourself, it just happens - instincts again I suppose.

& to add to what everybody else said, there have been some studies showing that is why women's voices are higher than men's. A way of nature making another connection between mom & baby.

actually, the whole high-pitch voice thing has been proven in so many studies to catch the babie's attention better, and to comfort them. thats why in cultures all around the globe its the natural thing to do.

young babies esp like higher pitched voices; moms tend to have a higher pitch naturally...survival i guess

actually, yes there is a good reason for doing it. Those different pitches will of course catch their attention more, and it helps them learn the different pitches of the languages and helps them develop language skills and helps them bond with their parents.. Heres a link to a good website with some more information about that.

http://www.talaris.org/spotlight_parentese.htm

&

http://www.healthywomen.org/resources/womenshealth...

Scientific, yes. Babies find higher voices more soothing and calming then lower ones.

actually it has been proven that babies prefer higher pitched voices and I think the reason babies calm when people talk to them like morons is because the baby thinks they are so stupid and just calms down because they feel sorry for the babbling person.

it's actually a characteristic of speech called "motherese" which is the high pitch language you are speaking of. it's natural when you are speaking to babies.