It takes a long time for little ones to master saying words correctly, and along the way they tend to have all kinds of cute ways to say things. It's tempting to repeat a word back to them exactly the way they've said it because it's so adorable - but I'm here to suggest that, where possible, it's best to repeat back correctly. Why?
FOR SPEECH SOUNDS.
Repeating a word back correctly is the BEST thing you can do to support your child's speech sound development. Some sounds are harder to pronounce and take longer to develop, so you should never correct your child (e.g. "No it's not 'dun' it's 'sun') but if you repeat the word back positively they get another opportunity to listen and take that on board. Most children learn most speech sounds just by listening, so the more good examples you provide; the better.
The sooner your little one can say the word accurately, the sooner an unfamiliar listener will be able to understand them. Yes YOU understand their cute way of saying things, but someone who doesn't know them as well won't. Being misunderstood can be upsetting and frustrating for children and it stops them from being able to communicate their wants, needs and interests.
Being able to say a word correctly is a huge bonus when it comes to learning how to write a word. If your child changes a sound or drops a syllable from a word - they're less likely to be able to write that word down.
So - say it back correctly. You can do this in a calm, non-threatening way that doesn't sound like a correction. Simply say the word or phrase back correctly before responding to their message. So in this example, the adult could say "where's the baby? I can see her - she's on the swing!".