Research shows that babies start to make sounds that resemble ‘ooh’, and ‘ahh’ and ‘ee’ first.[1]
Whatever languages you speak or they hear at home, it's probable you'll hear little 'oohs,' 'eees,' and 'ahhs' as they explore how to use their voice through what is known as ‘cooing’.
They use these noises to practise their vocal skills; their tiny tongue, mouth and lips are beginning to work in harmony with their vocal tract to generate vowel-like sounds. Your baby will likely produce these noises first, as will babies all over the world!
Because they begin life producing the same sounds, it means that all babies are born with the ability to learn every language.
Babies have an amazing capacity to pick up the sounds and patterns of any language they hear throughout the first year of life. This is because of the neuronal plasticity of their brains, which enables them to quickly adjust to and learn from the voices they hear in the world around them.
They gradually become better at tuning into their native language(s), as they hear them more often, making it easier for them to remember. And over time they’ll forget sound sets that are not from their own tongue.
Although babies are born with the ability to learn any language, their experiences greatly influence which language(s) they end up learning.
Babies who are exposed to multiple languages from birth or in their early years may later become bilingual or multilingual. And according to research, once they've learned more than one language, they'll never be confused about which language is which.[2]
There is no known maximum number of languages a child can learn.
We don’t know exactly how many languages is ‘too many’, however, it isn’t uncommon for children to learn three or more at the same time.
References:
[1] Cychosz, M., Cristia, A., Bergelson, E., Casillas, M., Baudet, G., Warlaumont, A.S., Scaff, C., Yankowitz, L., Seidl, A. (2021) Vocal development in a large-scale crosslinguistic corpus. Dev Sci. 2021 Sep;24(5):e13090. doi: 10.1111/desc.13090. Epub 2021 Apr 6. PMID: 33497512; PMCID: PMC8310893.
[2] Makhijani, P. (2017) Bilingual babies listen to languages — and don’t get confused. Princeton University.