Combining pro-drop with null morphemes

Question

Some languages combine pro-drop with null or zero morphemes – inflectional morphemes, more particularly. Turkish is an example of this. To illustrate, the verb istemek = to want is inflected as follows (in present continuous):

1Sg: istiyor-um
2Sg: istiyor-sun
3Sg: istiyor__
1Pl: istiyor-uz
2Pl: istiyor-sunuz
3Pl: istiyor-lar

Note that in the 3rd person singular, there is no morpheme – or at least not one that’s phonetically realised. So, in that sense, we have a null morpheme. (-yor- is the morpheme for continuous, but there’s no morpheme for person.)
Next, Turkish is a pro-drop language. To say e.g. I want to eat an apple, one does not have to use the first-person pronoun ben, as in Ben bir elma yemek istiyorum, but can instead say: Bir elma yemek istiyorum. Similarly, in the third person one need not use the pronoun o. To say He wants to eat an apple, one need not say O bir elma yemek istiyor, but can say:

(T) Bir elma yemek istiyor.

Now, (T) is the kind of sentence I am interested in, as it contains neither a personal pronoun nor an inflectional suffix. (More carefully, neither is realised at the surface.)

My question simply is whether anyone can supply another language that exhibits this – ideally a language where this happens in the first person singular. It’s fine if the language is merely null-subject and not fully pro-drop (i.e. allowing pronoun dropping only for subjects). Of course, I don’t want a language like Japanese or Korean, which lacks inflection in the first place.

Answer 1

Technically, English (and Turkish) imperatives are pro-drop and feature the null morpheme.

But what is arguably really going on here is that the Turkish present-progressive endings are like a compound with copula, and Turkish has null copula for 3rd-person singular. (The actual Turkish 3rd-person present tense is marked, eg etmek / eder.)

(This goes back to the etymology of -iyor. If I recall correctly, it is a relatively recent innovation, and had some literal meaning, which is why it works like a noun or adjective, not a suffix - no vowel harmony. And of course English present progressive also uses the copula.)

In that case, as we're counting a compound tense with the copula, then any pro-drop language with null copula and compound tenses would qualify. For example, Russian (past tense).

Answer 2

I've seen literature that advances the thesis that languages without "pro-drop" tend to have verb that inflect to distinguish some, but not all person/number categories (I think the typical examples used to illustrate this claim are English, French and German), while languages with "pro-drop" tend to either have inflected verbs that (mostly) distinguish between all the person/number categories, or verbs that do not inflect. This generalization is mentioned in the Wikipedia article on "Pro-drop languages".

This would imply that in a language with "pro-drop", a null affix would most likely only mark one person/number category, not several.

Based on what I've read, marking the third person with a null affix on the verb is not uncommon, although I don't have any numbers to give you. I haven't heard of this being a common strategy for marking the first person singular, although it probably exists in some pro-drop language.

Navajo is an example of a language with prefixes to mark subjects and objects where a third-person subject (singular or plural) is marked with a "null" affix.