Algorithms that can determine whether a string is an English sentence? In particular, I'm looking for something that can distinguish between complete sentences and sentence-like grammatical structures like clauses and phrases. It would also be very helpful if a library with this functionality was shared, but even a link to a paper would be appreciated.

For example- I would like "False" to be returned for strings like: 

'Via The Daily Currant,' 

“Waiting for the rain to stop”

'查看更多请返回网站主页。'

'*  *  *'

I would like "True" to be returned for things like:

"This is a complete sentence."

"I don't think there will ever be a Half Life 3, unfortunately."

Thank you!
There is a library for python 

https://pypi.org/project/langdetect/

This field is called "language detection" and it is quite active.