Beginning from birth, babies everywhere follow a similar pattern of acquiring their first languages (regardless of signed or spoken) according to their individual biological timeline -- from cooing and babbling to one-word utterances, two-word utterances, and eventually, to full-fledged language.
Dr. Petitto, a renowned neuroscientist, explains that the brain does not discriminate the difference between sign language and speech language (or at least, between ASL/Ameslan and English).
ASL is Juli's mother language and it has been her primary language in a natural, ASL-native environment. Her language development in ASL parallels to the same timeline of a spoken language.
The baby Juli, who has been exposed to ASL from birth, produced manual coos, first syllabic babbles at 6-7 months, and referential words at 10 months. Regardless of the modality (signlan or speech), her timeline follows the universal pattern of language acquisition.
Although English has been also, though minimally, exposed to Juli from birth, Juli's speech follows the same timeline from vocal coos to vocal babbling to first words at about the same times in parallel. However, she primarily acquires ASL as a first language and English as a second language. She listens in the English-speaking environments outside her primary ASL surroundings. Whenever she understood English, she usually responded in ASL.
Lately, Juli gradually began to utter some more English words such as: door, catch, stop (sounded as "sop"), bird, roof, window, wall, star, ho-ho-ho, and so on.
The spoken English word ball was one of the first words long time ago at the emergence of the first ASL words on the same timeline of language acquisition.
From this on, Juli continued to acquire English as a second language at age two. This parallels to other bilingual toddlers who acquire a second language at age two (primary language at home/family and another language outside home/family).
The following referential ASL words and phrases that Juli used this week: milk upstairs, more puzzle, close-door calmly, some more shown in the video above, and other ASL words mentioned in the past months.