Spanglish

My professional interest has always been culture change. And part of culture change is language change.
I am now obsessed with the juxtaposition of English and Spanish, particularly in Texas.
For more than twenty-five years I have noticed that TexMex seems to have lost the use of the Spanish estar (one form of to be). In formal Spanish, our English verb to be has two forms. Ser is used for a "state", as in Yo soy una mujer. Estar is used for place, as in Yo estoy en mi casa.
Tex Mex seems to be using only ser for both senses.
Last week I was trying to explain this to my companions in a restaurant. I asked the Hispanic waitress, "What does yo estoy mean in English?"
She did not know.
Later she came back and told me that it meant "I am here."
People use "Yo soy aqui."