Singing waiata to pēpi massively helps language development.
When pēpi is born they are able to respond to certain tones with a matching tone.
Singing and tone matching gives a basis for learning language.
You don’t need to be a good singer in order for them to get the advantages for their language development.
By singing 2-3 different waiata to your pēpi in te reo Māori you are exposing them to around 60 different Māori words and the unique sounds, giving them a great start if they wish to learn te reo later.