Now you've flagged it up to the teacher I would hope they take control of this and address it in a low key way i.e. monitor the other girl's interaction with others and reinforce the 'Kind words' message in circle time etc. They may already be aware of the behaviour but didn't see the two instances that upset your DD.
Tell your DD to tell the teacher or TA if anyone blocks her way again, or makes fun of the way she talks.
My DD is in reception at school. She is a quiet little girl and really quite shy. She has minor speech problems which probably make her even quieter.
Another girl in her class (who she went all through nursery with) has started to make comments on her and her things. She has a Tigger lunchbox and the girl has told her that its for a baby and that she talks like a baby too. Yesterday she came home and said the girl wouldn't let her in the reading area in class and blocked the door with her arms and legs so my DD had to climb in around the back. She apparently also made another little girl cry.
I have left it s few weeks but my DD was lying in bed last night and she said to me "Mammy I hate **, she makes me sad"!
I've rang the teacher who is hopefully ringing me back today but I'm just so worried that it could get out of hand