Strictly speaking no, it is not necessary, CDS is not universal among world cultures and as such plenty of children learn to speak with a lack of CDS.
It's only required that you speak to the child, not necessarily use CDS patterns.
nativist view.
Infant-directed speech, also known as baby talk or motherese, positively impacts language development in young children. This type of speech is characterized by higher pitch, exaggerated intonation, and simplified vocabulary. Research shows that infants are more attentive and responsive to infant-directed speech, which helps them learn language more effectively. It also aids in developing their vocabulary, grammar, and communication skills.
Formative speech refers to language input that helps a child learn and develop their language skills during the early stages of language acquisition. It involves providing appropriate models of language that help shape the child's linguistic abilities. Formative speech plays a crucial role in helping children understand how to communicate effectively.
caretaker speech tends to be slower speech with short ,simple words and sentences which are said in a higher-pitched voice with exaggerated inflections and many repetitions of essential information.
Anne Dunlea has written: 'Vision and the Emergence of Meaning' -- subject(s): Blind Children, Language, Language acquisition, Speech acts (Linguistics)
Werner F. Leopold has written: 'Speech development of a bilingual child' -- subject(s): Bilingualism, Language acquisition
Duncan Markham has written: 'Phonetic imitation, accent, and the learner' -- subject(s): Second language acquisition, Speech perception
Most cultures use some form of child-directed speech, characterized by a higher pitch, repetition, and simplified language. However, the specific ways in which caregivers interact with children can vary depending on cultural norms and values.
Peggy J. Miller has written: 'Amy, Wendy, and Beth' -- subject(s): Language acquisition, Speech and social status
King's Speech directed by Tom Hooper.
Speech therapists examine, diagnose and treat patients with speech disorders. Classes they must take include Speech and Language Acquisition Course, Speech Anatomy and Physiology Course, and Speech Therapy and Phonetics Course, to name a few.
Understanding speech in a foreign language is often difficult at first, especially if the speech concerned is not directed specifically at you and if there is background noise, as in a bar, for example. Listening comprehension needs developing through practice.