Which "english" is proper?

As others have said, English is evolving. One already sited example is good and well. Technically “good” is an adjective and “well” is an adverb. It is correct to say something is “good English.” but you would say that someone “writes well.” This distinction is fading as using “good” as an adverb as well as an adjective is slowly being accepted. Saying someone “writes good” is incorrect from a strict grammar point of view but in a few years or decades it will probably be accepted.

This battle has already been lost with the word “fast.” At one time “fast” was properly an adjective but years of it being commonly used as an adverb made it acceptable in both places, otherwise we would have to use “rapidly” or “quickly” in its place. I’m not sure why we don’t just say “fastly” and “goodly” to be consistant since that is the standard way of inflecting an adjective into an adverb..

Of couse what is proper English will always depend on the context. Computer people have a habit turing turning verbs into nouns (e.g. the startup, the backup, the upgrade) and nouns into verbs (Let’s database that, provision those servers). Most treat the plural data as singular saying “the data is….” instead of “the data are…” Among computer people these things are all proper.

Some authors use poetic license to intentionally break the rules of grammar for effect.