Hi - retired TA (male) with 20 yrs experience KS1 classes -
As others said, don't worry about it at this stage.
But if DD is behind in speech and language, what is being done to help that situation, and are there any obvious causes? (illness, trauma, changes in her life, etc). Might there be any hearing loss?
Unfortunately, these days there is so much poor speech on TV, radio, etc that, even on programmes aimed at children, accurate speech and diction is neglected. For instance, "t" sound is so often missing from spoken words like "party", "tattoo" etc, that some children grow up never having heard words pronounced correctly. A few secondary pupils can spell "fink" ("think") because that is what they hear spoken at home.
If there are no physical causes of the speech problem, then adults around her taking care to be as accurate as possible in their diction, may help a bit.
If you ARE using phonics, make sure the correct sounds are used (I have known plenty of teachers who are STILL saying sounds wrongly).
Good luck.