Unexpressed subjects in Thai, Lao and Vietnamese?

[Ezra Van Everbroeck]

Dear all,

I'm a Ph.D. student in the Linguistics progam at UC San Diego. For my
dissertation, I'm looking at whether connectionist neural networks have
problems learning the same language types which are also unattested or
infrequent from a crosslinguistic perspective. One of the types which the
networks have problems with is an SVO language with omission of the
unemphatic subject (~ pro-drop), but no case-marking or agreement.

However, there appear to be some such languages in South-East Asia that
allow pro-drop, despite relatively poor morphology. I have already looked at
Mandarin in some detail and think that I can account for it because it has
some other properties which make it possible to (usually) distinguish
between nouns and verbs - i.e. what is needed in the models to make such an
SVO language learnable. These features in Mandarin include prepositions and
classifiers (which help indicate NPs), as well as aspect markers,
auxiliaries and co-verbs (which all help indicate verbs). Mandarin also
uses a lot of fixed phrases and prefab constructions which would be helpful
to the language learner.

Some of the other languages spoken in the region also appear to have a
similar set of features, but I'm wondering whether anyone on this list has
information on how often or under which conditions unemphatic subjects are
actually omitted in e.g. Thai, Lao and Vietnamese. The literature on
Vietnamese suggests that subjects can be left unexpressed only in
existential sentences and in coordinated clauses. Thai and Lao are described
as being more permissive in this regard, but I have been unable to find
anything more precise than that unexpressed subjects are "common".

So, any information will be much appreciated.

Many thanks in advance,

Ezra


P.S. If you know of other languages which combine these four features, I
would also like to hear about them.

- a basic SVO word order
- no noun case system
- no verb agreement system
- option to omit unemphatic (but referential) subjects (~ pro-drop)