There are studies of this. It's best to search in Google scholar to filter out (some of) the crap:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Miam...
The majority of the work focuses on sociolinguistic aspects of Spanglish, but there are also grammatical investigations. Here's an example dissertation that cites some other studies along the same lines:
https://digitalcommons.spu.edu/cgi/viewcontent.cgi?article=1...
There are studies of this. It's best to search in Google scholar to filter out (some of) the crap:
https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Miam...
The majority of the work focuses on sociolinguistic aspects of Spanglish, but there are also grammatical investigations. Here's an example dissertation that cites some other studies along the same lines:
https://digitalcommons.spu.edu/cgi/viewcontent.cgi?article=1...