hmmm, my nephew had fixations like that, turned out to be autism
Thanks for your answer, good to know other kids have horse attachments and want real horses. I would not change the schools, eventually she'll have to get used to English and communicate properly.
Maybe she's clinging onto it for some sort of security reason. My 4 yr old loves horses too and plays with lots of horse toys but doesn't seem as "attached" to them as your daughter does... which isn't bad, my daughter is always asking for a real horse and sometimes still doesn't understand that she can't have what's on TV all the time. I bet she just wants a real one and that maybe that's her way of asking.
I think that the difficulty of being bi-lingual is probably a good reason for her to be a little frustrated and to cling to something such as her favorite toy while at school.
Have you spoken to an administrator at her preschool or possibly the school system administration to see if there are any bi-lingual teachers or any other places that might be better suited for her - more kids/teachers speaking the other language? There must be something that can be done to make her feel like she's not alone.
How long has this been going on? If its been more than 4 weeks, then you should call her dr to check this out.
Also - Any other problems? Is she well behaved? Gets along with other children in an age-appropriate manner? Keeping up in terms of other developmental milestones? Any coordination - small motor or gross motor skills issues?
Have there been any major environmental changes for her -- like moving, family changes, anything like that?