DD is just 4, and has sort of taught herself to read and write - mainly by copying older siblings, I think.
She has recently been writing short sentences, or drawing pictures with captions. Eg today she wrote "daddy and momie and DS and DD hav bin on holede [holiday] in fros [France]"
Because she is self taught, she doesn't know that much about spelling - though I think she must be remembering some things that she has read -, and she doesn't respond well (putting it mildly) to being told she has missed out a letter/used the wrong letter etc.
So I tend to just act very enthusiastic at all her efforts. DH thinks we should (gently) point out errors, otherwise she'll assume the incorrect way is right.
I should add that we don't live in an English-speaking country, and she isn't at school yet (and won't be until she is 6), so her only English input is from us as her family, and she won't be learning to read and write in her second language either for another 2 years.
DH doesn't want bad habits to be entrenched; I think she is showing enthusiasm and we should just be enthusiastic in response. I suspect we need the middle ground, but not sure what it is.
She does seem to somehow have a grasp of phonics, as she sits there sounding out words before writing them.