The emergence of marginal babbling
As the grandpa interacted with nearly 5 months old baby Juli held by the grandma behind, Juli was trying to sign something. Signing-like. Juli's father and I quickly turned and looked at each other.
The father first responded in ASL, "Was Juli trying to sign?" imitating Juli's movement. I replied, "I was seeing the same thing."
Next morning, as I greeted Juli and again she was signing. Video was never captured. When I do, that specific signing didn't occur.
Marginal or pre-canonical babbling is characterized by an unit of consonant and vowel (e.g. "ba", "da, da", etc.) at 4-6 months of age.
In studies, the onset of marginal babbling in hearing infants typically co-occurs with hand banging or some type of rhythmic motor activity at around 4-6 months of age.
Keiko Ejiri (1998) observed that "On average, 40% of rhythmic manual activity co-occurred with marginal babbling, whereas less than 5% of rhythmic manual activity co-occurred with other categories of vocalization. Further, more than 75% of all marginal babbling was accompanied by rhythmic manual activity." (Language Acquisition by Eye, pp 15-16.)
This study refers marginal babbling to speech or vocalization, but how would linguists explain about a relationship of marginal babbling in sign language and rhythmic manual activity? How might marginal babbling in signlan look like?
Juli responded by moving her hand. Not much she could physically turn the page, but her eye gaze, the movement of hand, and her attention tell a lot. Her manual movement appears to be a single syllable.
Manual play, the precursor to canonical babbling
Toward the end of that month, hand was the theme the last week. Early that week Juli paid closer attention to fingers and hands of not only hers but also adults' hands.
Whenever adults put their fingers in Juli's hand, Juli brought them into her mouth, not everyone's but mostly good friends. Sometimes it felt awkward, sometimes a bit weird. But, I gently reminded myself of the beauty of nature.
Video clip: Joey interacted and played with Juli who explored his hand. He taught her how to do a high five. He demonstrated. And he practiced it with her.
A few moments later, Joey and I finished chatting. Before we parted, he gave Juli the last high-five and she responded! Joey burst in delight, "she's learning!" No capture on video, shoot!
Video clip: I asked Joey to do a high five with Juli again this time in hope to capture on video. Second was not always the better one.
A month later (m6w2), Joey greeted Juli with the usual high five as soon as we entered the meeting room at a bilingual school. Joey raised his high-five hand. With no hesitation, Juli raised her hand so perfect! I freaked out for the camera. The moment was gone.
Video clip: "Hello, hello! (handshake) Nice to meet you! (handshake) Hello, hello!" It provided Juli some more manual play activities.
The ASL verb meet is normally inflected to meet-you in a single verb, but I was doing parentese to make a clear pronoun.
Video clip: Mother playing cross-handshakes with the baby.
Juli showed her interest in my hand. She tried to reach for it. Eventually, she got it and brought it into her mouth.