DD 2.9y substitutes s and f with d

[ClapTrap]

Hi, my DD who is 2.9y has always had pretty good vocabulary and has been able to converse quite well from about 15 months.

However, I am beginning to get a little concerned that she is continually substituting s and f with a d sound at the beginning of words. She can make the sounds in the middle or ends of words. She doesn't seem to show any sign of improvement. She is intelligible to me and OH, but MIL and FIL constantly misunderstand what she has said (and they look after her quite a bit).
Should I be seeking SALT or chill out and she will get it in her own time?

My DD did this. Her favourite toy was supposed to be Floppy dog - she called it Doppy Dog. Which DH, by analogy with her wearing 'deep doots' at night, interpreted as Soppy dog, which he has remained to this day.

It did resolve in its own time, though I did help her with 'F' by getting her to make 'bunny teeth' (try it, I think you'll be able to see what I mean). IIRC I encouraged some sss hissy snake noises too.