When an adult sticks his/her tongue out at their newborn within 72 hours from birth, the newborn is able to imitate by his/her tongue out. Researcher Dr. Andrew Meltzoff, PhD, discovered this ability in hospital nurseries.
Newborn is born an avid learner and is ready to imitate. However, if you snap your fingers or smack with your lips, maturally the baby couldn't imitate either of these. Her/his brain is not developed with complex motor skills yet other than sticking out the tongue.
Baby begins to make cooing sounds (with increasing goos, gurgles, and grunts) and cooing visues at around month one when they start to respond to parents' voice and/or signing. Babies make cooing visues in response to native signing parents. Parents are encouraged to respond to their babies even if these babies just coo. Interaction is important. This marks the beginning of language development.
My thoughts are that baby typically coos a single vowel like "ahhh". Whereas in sign language, baby coos a single visue like the "5" handshape. The vowel "a" and the prime "5-handshape" are two the simplest phoneme/prime (one of the smallest units of language) in speech and signlan respectively.
Juli (at 2nd week) in the video clip above appeared to imitate or at least attempted to imitate manual movements. I first recognized my baby Juli doing manual cooing.
An fluent ASL-speaking mother once uploaded her video on YouTube where she signed milk to her baby within the first weeks from birth. The baby responded with a faint imitation or a form of cooing.
Scientists and linguists including neuroscientist Dr Petitto have known about manual cooing for a long time.
Gesundheit! Every time the baby Juli sneezed, we uttered health to her. In the video above, the signer repeated the signed word health several times.
As the baby moved her handshape onto her neck, the father showed another word embarrassed to show a different ASL production (equivalant to pronunciation) that the baby was making.
Starting in the first weeks after childbirth, I also had noticed that Juli had formed her reflexive handshapes from time to time as follows: "i", "m", "n", "t", and "s".
Though, these reflexive handshapes would disappear within the next month later or sooner as movements would begin to become smoother and a little less jerky as the baby's muscles and nervous system continues to develop.
Even though increasing goos, gurgles, and grunts continued, Juli also made "goos" in her signing in parallel. Juli moved her arms when I talked with her. She apparently responded to me. I responded to her when she talked through manual cooing.
Sleeping and waking hours had begun to form into a pattern . That is, the one month old baby Juli slept more hours in the nights and stayed awake more in the day times.
Now that Juli's eye contact had gradually increased. She became more wakeful, so thus more time for interactions with her. Juli had been exposed to ASL on a daily basis with me, her father, grandparents and relatives.
Videoclips: Great Aunt AG asked whether Juli has received a name sign yet. No, not yet. She talked with Juli, telling her, "You will receive a name sign, not yet now. Wait patiently and mother will observe your traits and find the right name for you."
AG chatted with Juli in ASL. Roughly translated as "See you're signing.. signing. You can sign. Mother will teach you to sign." Juli moved her hands that resembled to "yes". AG was delighted by this coincidence, "Yes, you will be signing. Yes, signing."
One night Juli was fully awake for a long while without fussing for feeding or another need. I took this opportunity to interact with her with the camera set up.
When shooting video, Juli kept noticing the black camera. Despite this distraction, she however focused on me most of the time when I talked or played with her.
Some common ASL vocabulary that I used lately with Juli were as follows: milk, bath, more, health (after sneezing as she sneezed often), mother, father, "I love you", beautiful, sweet, and some more.