Your baby's wonderful gurgles and noises have been helping them develop their vocal cords and interpret language. They will have begun to discriminate between pitch and tone, and they will likely use a variety of sounds when babbling and interacting with others. As they experiment with their own emerging sounds, the sounds they generate when communicating are beginning to sound more like singing.
The voice box is essentially a human instrument. The sounds that your baby produces are called harmonics. Harmonics are thought of as the source of the sound and sounds are made by the vocal cords. Air comes up from the lungs and passes through the voice box and throat. There is an enclosed space within the throat and this changes shape and size to make a wide variety of sounds. A low sound will be made from a wide vocal tract whereas a high sound is produced from a narrow vocal tract.
It is around now that your baby will be starting to use a wider variety of sounds when communicating with familiar people [1]. Their voice will be more controlled, and they may now be starting to produce a range of sounds with more distinction of high, low, loud and quiet ranges. [2] These new ranges are being produced by your baby's developing voice box and is offering them an opportunity to join in with, or copy the melody of familiar songs.
Songs and music are appealing to your baby as the soft melodic tones, along with the movements and gestures associated with singing, easily draw their attention. Songs link with repetitive movements and actions which can support the development of motor skills. Finger rhymes, individual limbs and whole-body movements are associated with singing. [3] Your baby may start to link their emerging vocal sounds and body movements to the songs they are familiar with.
Babies learn to speak through observation, listening, and repetition. They enjoy nursery rhymes and songs and as you sing your baby will be watching you and listening to the noises you produce. Your baby is learning a variety of melodies while listening to singing, whether it is done by a person or by listening to music. These melodies provide an opportunity for your baby to try to imitate the tune.
When you sing together, you are connecting with your baby. Singing links with skills in other streams and is important for cognitive development, language, and emotional development.
Over the next few months, your baby will become more familiar with particular songs. Their throat and voice will continue to develop and you may hear them producing some ‘words’ to some of the songs. The words may well not be clear, correct or in the right place but your baby is experimenting with sounds and rhythm. Having lots of opportunities to listen to and join in with music and songs will support your baby's language and literacy skills.
References:
[1] Gotzke, C. & Sample Gosse, H. (2007). Parent Narrative: Language 10 - 12 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 8. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development
[2] Gotzke, C. & Sample Gosse, H. (2007). Parent Narrative: Language 13 - 24 Months. In L.M. Phillips (Ed.), Handbook of language and literacy development: A Roadmap from 0 - 60 Months. [online], pp. 1 - 8. London, ON: Canadian Language and Literacy Research Network. Available at: Handbook of language and literacy development
[3] Vihman. M.M. (2014). Phonological Development. The First Two Years, 2nd Edition. Wiley Blackwell