DD not answering adults

[Auroraspyjamas]

My DD has just turned 5 and started school. She has found it quite easy to make both close friends and be part of a group and is chatty, loud and silly with kids her own age. Shes also like this at home and with close adults like her uncle and grandparents. However I’ve noticed when we bump into less well known adults like neighbours or her friends’ parents she is very shy. She answers questions only with little nods, sometimes mumbles one word answers or even ignores the question entirely. How typical is this? And if you experienced it was it a phase, did you do anything to address it etc? We tend to not jump in to answer for her but wait and leave space and also don’t pressure her to speak in front of adults but when back at home will gently enquire what was happening when she eg ignored a question and she says she feels shy. We try and encourage her to order food herself at restaurants and eg hand over money for a toy at charity shop to grow her confidence but we don’t really push it if she’s not keen to avoid making it into a complex. Thoughts? Advice? Anything else we should be doing? How concerned should we be etc?

Sounds like you're about right, let her find her own voice.
Adults are massive compared with 5 year olds.
I think it's natural to be wary of less familiar adults, and probably not the worst thing, to be wary.

Selective mutism?

We try and encourage her to order food herself at restaurants and eg hand over money for a toy at charity shop to grow her confidence but we don’t really push it if she’s not keen to avoid making it into a complex. @Auroraspyjamas

I would stop anything like that now and give her a sense of complete safety around adults.
Even asking her if she wants to order her own food (where you're allowing her to say no) can start to cause anxiety.

Completely alleviate any pressure to engage with adults she doesn't know.

You can build confidence for now by helping her to reflect on her feelings when with trusted adults (family, her teacher etc). Hopefully she will identify feeling safe, comfortable, able to be herself, she might need your help with the words to describe themselves feelings.

In time hopefully she will naturally begin to engage more herself with other adults such as at the checkout or library.

Pretty normal I think.
One of my DC was particularly shy like this when they were tiny and can still be a little now, but they’re perfectly able to speak up in class, show parents around school etc
I used to explain that if you look at someone when you talk to them, or you say thank you or whatever, it makes them feel noticed and appreciated. We worked on the basis that a polite thank you is essential, eye contact it’s important if they possibly can and that I’d help out if they got stuck. 5 is very little.

I think this is really normal OP. I can remember my DS being like this, he's now an articulate teenager. I wouldn't worry too much.

Do not tell your 5 year old to look someone in the eye when they are talking to them.
That will cause even more shyness

She will overcome it in her own time