Why do not people use subject and am,is,are in social media? [duplicate]

• "Thought you'd never ask" is "I thought you'd never ask" with "I" omitted.

• "Hope this helps" is "I hope this helps" with "I" omitted.

In English grammar, normally every sentence should have a subject, right?

My first thought is that these two examples are so often used that they are like set phrases. But these are not really set phrases. You can alter the words after "thought" and "hope".

Another possible explanation is the tendency to drop the subject if it is the first person pronoun. It seems that in many languages, such as Spanish, Italian and Japanese, the first person subject is usually omitted. Maybe English is going the same way? (Not exactly the same, since in Italian, verb forms change according to the person, so the subject is not necessary to understand who one's referring to.)

And, apparently, such omission is more common in spoken English than in written English.

Are there more examples of such first person subject omission? How frequent is it?

This is due to a phenomenon that occurs in intimate conversational spoken English called "Conversational Deletion". It was discussed and exemplified quite thoroughly in a 1974 PhD dissertation in linguistics at the University of Michigan that I had the honor of directing.

Thrasher, Randolph H. Jr. 1974. Shouldn't Ignore These Strings: A Study of Conversational Deletion, Ph.D. Dissertation, Linguistics, University of Michigan, Ann Arbor

To quote:

• (1.16) Gotta go now.
• (1.17) See you next Tuesday.
• (1.18) Too bad about old Charlie.
• (1.19) No need to get upset about it.
• (1.20) Been in Ann Arbor long?
• (1.21) Ever get a chance to use your Dogrib?
• (1.22) Ever get to Japan, look me up.
• (1.23) Good thing we didn't run into anybody we know.
• (1.24) Last person I expected to meet was John.
• (1.25) Wife wants to go to the mountains this year. [all from Thrasher 1974 p.5]

"The phenomenon can be viewed as erosion of the beginning of sentences, deleting (some, but not all) articles, dummies, auxiliaries, possessives, conditional if, and [most relevantly for this discussion -jl] subject pronouns. But it only erodes up to a point, and only in some cases.

"Whatever is exposed (in sentence initial position) can be swept away. If erosion of the first element exposes another vulnerable element, this too may be eroded. The process continues until a hard (non-vulnerable) element is encountered." [ibidem p.9]

In general, exposed first-person subjects are vulnerable in statements, and second-person in questions, and any exposed pronoun is vulnerable if it is recoverable from later in the sentence.

• (3.2) Can't do it, can {I/you/he/she/they/we}? [ibidem p.59]

Let me reiterate that this phenomenon only occurs in speaking English, and in other informal communication systems like email and txting that work like speech. It is not good formal written style, except for reporting dialog in a story.

The "implied" subject is a common feature of conversation and some writing, especially fiction (not necessarily limited to dialogue). Where the subject is clear, it is frequently omitted. This is a form of ellipsis.

Great. [For "That's great."]
Such a waste. [For "That is such a waste."]
Coming! [For "I'm coming."]

There are many more. In each case, the subject will be understood, usually from something someone else has said.

Person A: You don't have time to talk with Martha.
Person B: Not true. I've moved my schedule around.

There's even a famous advertising campaign in the U.S. featuring people from different walks of life who are sporting a "milk mustache" (milk on the upper lip from having recently drunk some milk). The headline? "Got milk?"

But the implied subject is most often seen in imperative statements:

Go now.
Stop!
Get up.

In the above, the subject is you, and is hardly ever included.