Term for omitted pronouns?

Question

In informal German, e.g. spoken conversation or text chat, it is possible to omit certain personal pronouns and sometimes inflected forms of sein ‘to be’, too (similar to Russian).

Ich gehe nachhause. → Gehe nachhause.
‘I’m going home.’

Wir sind gleich da. → Sind gleich da. → Gleich da.
‘We’ll arrive there soon.’

Es ist kein Kuchen mehr da. → Ist kein Kuchen mehr da. → Kein Kuchen mehr da.
‘There’s no cake left.’

Es regnet. → Regnet.
‘It’s raining.’

It works best and is most common for first person pronouns, either singular or plural. If a third person pronoun is omitted, it usually implies neuter, i.e. es and neither er (m) nor sie (f). Interestingly, it’s not only used if the inflected verb is unambiguous on its own, e.g. ich bin, du bist, es ist; wir sind, ihr seid, sie sind. However, elision may be suppressed if it would create ambiguity, e.g. not *geh’ nachhause which would be equal to the imperative, although ich geh’ nachhause is pretty much standard now.

Second person pronouns are only omitted in questions, but more often they’re just shortened, becoming a verbal enclitic:

Bist du gleich da? → (Bist d’ gleich da? →) Biste gleich da? → Bist gleich da?

Geht ihr nachhause? → (Geht ’r nachhause? →) Gehta nachhause? → *—

What is the linguistic terminus technicus for this phenomenon? I’m looking for one that is more specific than ellipsis.

Answer 1

I have encountered various analyses of and terms for the phenomenon, topic drop being one of them and left edge ellipsis being another. I have used the latter term, i.e. left edge ellipsis (LEE), in my writings.

The examples in the question all submit to an analysis in terms of left edge ellipsis (LEE). LEE occurs in relaxed registers (everyday conversation, emails, text messages, etc.). The ellipsis reaches in from the left edge of the utterance, e.g.

 (Do you want) Coffee or tea?

 (Have you) Been working a lot lately?

 (I am) Quite tired. (I) Will go to bed soon.

LEE cannot occur if the elided material is not at left edge of the utterance, e.g.

 *Now (I am) quite tired.

 *Soon (I) will go to bed.

The German examples in the question all submit to an analysis in terms of LEE. In fact the ellipsis of just a 1st or 2nd person pronoun is a particularly frequent type of LEE in German, English, and many other languages.

I can list a couple of sources (not by me) that discuss the phenomenon in its various forms if anyone is interested.

Answer 2

In German, subject pronouns in the Vorfeld (spec-C) can be omitted. (I think Hubert Haider discusses this phenomenon in one of his books.) Note that this is not possible in subordinated clauses:

 1. a.  Ich gehe nach Hause.
    b.  Gehe nach Hause.
 2. a.  Er sagt, ich gehe nach Hause.
    b. *Er sagt, gehe nach Hause.

Note that (2b) is ungrammatical even though a subordinating conjunction is missing in (2.a). The word order in (2a) clearly shows V2-order, which is associated with main clause word order.

Concerning your second set of examples, you are quite correct in assuming cliticization. The position, in which this is possible in many languages, is called the Wackernagel position, technically the second position in the clause.