Parentese (known as "motherese", an older term) is defined as "a type of baby-directed talk or 'baby talk' which many parents use to communicate with their infants." It is found in many cultures around the world. And, of course, also found in signed languages.
In spoken languages, a parent speaks parentese to the infant in a high-pitched voice along with a slower rhythm. Speech is clear and has exaggerated intonation with longer vowel production. Words or phrases are repeated. the parent pauses long between sentences or phrases to allow the child to think.
In addition, the parent expands what the child says. E.g. child, "cat." Parent, "Yes, it is a cat." "The cat likes you, too." "The cat wants to be friend with you." She/he may use facial expression, manual gesture (e.g. pointing), and prolonged eye contact.
Studies show that infants prefer baby talk opposed to adult talk. Many people think that this type of talk is "dumbing" the child down; however, study shows that babies learn language more efficiently. Although, many parents do adult talk with their infants, which may benefit too.
As a native ASL signer, I find myself talking naturally in parentese in American Sign Language (ASL) with my baby "Juli". But, I also found myself using adult talk in ASL with her, usually when everyday life topics are not concerned to her. E.g. I explained what I was doing on the Internet, seeking information on a product to buy.
Similar to some characteristics of speech parentese, the following typical characteristics of parentese in sign language are:
Non-manual grammar is highly integrated with the manual system. Two functions in facial expression in American Sign Language are: affective and grammatical (or linguistic).
An example in facial grammar is a non-manual marker for a wh-question in which an articulator burrows his/her eyebrows for a wh-question and raises her eyebrows for a yes/no question as well as for topicalization and a rhetorical question.
Affective and grammatical expression on face may look similar to a non-signer's eye. For example, when eyebrows are grammaticaly burrowed, it may look like signer's mad, disappointed, or disgusted to a naive hearing outsider who knows nothing of sign language.
However, native and highly fluent signers are adept at distincting between emotional and grammatical facial expression.
In parentese, studies have shown that native-signing parents use different facial grammar with babies. For example, native-signing parents intuitively modify their facial grammar to a more pleasing affective facial expression. E.g. raising eyebrows instead of burrowing eyebrows for a wh-question.
Until these infants grow older enough (usually at around age two), the parents switch to using proper facial linguistic markers.
Also see nursery rhymes in sign language.
This documentation project follows a baby's language acquisition, literacy development, and phonological acquisition in sign language, specifically ASL, week by week from gazing at birth to manual babbling, to first words just before the first birthday in a natural native-ASL environment and visual culture.
The second-year and third-year documentation continues to follow the same child's language and phonological acquisition and literacy development in ASL on a weekly basis from the one-word stage to two-word and multiple utterances.
The documentary continues to follow the same child's ASL language and literacy development on a regular basis from age three to four. It surveys ASL phonological acquisition and more complex utterances.
These posts on ASL-English bilingualism, language acquisition, and bilingual education may be of an interest for parents who raise a bilingual-bimodal child in ASL (or another signed language) and English (or another written and/or spoken language of its respective) as well as informative and educational for ASL specialists, educators, and professionals.