Further to Carsten's question as to the development of trigger languages--

If Proto Austronesian was (as seems likely) a trigger language, then the
modern descendants show developments to:  (1) trigger languages, as most
Philippine languages (2) accusative languages (Malay/Indonesian and many
others) (3) ergative or ergative-like languages-- some Polynesian langs. are
said to be ergative, others like Buginese are ergative-like (in that you use
different subject/object affixes depending on transitive/intrans. verbs--
but there's also a connection with definite/indefinite).

laoka?, laoko, laoi /lao+ka?/-ko/-i/ 'I - you - he/she go(es)'
mitaka? asu (mita+ka?) "I see a dog"
uitai asue /u-ita-i asu-e/ 1sj-see-3oj. dog-def "I see the dog"
naitaka? asue /na-ita-ka?/ "the dog sees me"
uitako "I see you"

Carsten also wrote:
>That's also one thing I haven't fully
> understood yet, I mean why transitivity is important for
> Basque verbs. I know what the terms (in/di)transitive mean.

It's important because most trans. verbs require one auxiliary, which marks
both subject and object as well as tense, intransitives another, which marks
only subject and tense. A handful of verbs, of both types, have special
conjugation that doesn't use the aux.

I recall there's a large number of periphrastic verbs, usually denominals,
that are treated as transitive even though in most languages they'd be
considered intransitive-- like 'sneeze', in Basque IIRC it's _sneeze (noun)
make/do + trans.aux._

>  > > I mean like in the
>  > > example I gave, "to invent" -> "being invented", where
>  > > "being invented" is "invent.CAU".
>  >
>  > This sounds more like a passive to me than a causative.
> Yeah, actually you're right. Nevertheless I don't see why I
> should not form stative passives with the causative. IMO,
> something is "caused to be done" after all.
That's possible. Consider:

Stative: The door is open.
"Causative": John opened the door -- which can be viewed as either "John
caused the door to (become) open" or "John caused the door to be opened". I
think there's a question of direct/indirect causation here, but there's
certainly room for ambiguity.

ObConlang: Kash stative > causatives are generally active verbs; but there
is a series of verbal forms meaning "able to... ~able to be..." where,
especially if the base verb is transitive, the meaning is usually passive:
tikas 'to see' potikas 'visible' and many more.