These three kinds of induced mental states would correspond to our assertions, promises and requests, respectively. (I didn't include questions because questions are requests for information.)
Do these aliens have language? I think a standard answer would be negative. Normally, language acts as an intermediary between the speaker and states of the form (a), (b) and (c) in the listener. In the telepathic aliens, either there is no intermediary or the intermediary is merely causal--say, waves in a psi field. So even if there is an intermediary, it lacks the conventionality, normativity and grammaticality that seem to be marks of language. Moreover, in language we know it, it is the listener who processes the incoming utterance and turns it into a mental state like (a), (b) or (c).
For now suppose the version of the alien story that involves waves in a psi field as a causal intermediary. I think the differences are not sufficiently significant to mark the aliens as lacking language. Conventionality is a feature of human languages which are developed by mimetic evolution and are passed on mimetically. But there is nothing absurd about languages that develop instead by genetic evolution. (It may be that some animals have them.)
There is no reason why the aliens' communicative methods could not be normatively laden through and through. They might, for instance, be subject to an Aristotelian teleology according to which one ought not telepathically induce states of the form it seems that x telepathically informs me that s unless s, or unless one believes s, or unless one knows that s, or whatever the correct norm of assertion is.
If the aliens are in a world relevantly like ours, there will be regularities about the correlations between the waves in the psi field and the resultant mental states, and these regularities may very well be isomorphic to grammatical ones.
Finally, I do not think the question whether the listeners process the inputs or not matters much. Most of the time, our linguistic processing is automatic and unconscious. We could imagine a person whose automatic and unconscious linguistic processing is replaced by a prosthesis that produces the relevant mental states. We could talk to such a person and she would count as hearing us. Furthermore, we can imagine that in the aliens there is some minor processing, such as amplifying faint psi field waves. The presence or absence of amplification surely doesn't mark the difference between language and non-language.
But now suppose that we grant that the aliens have language. That means that an account of what language is must apply both to the aliens and to us, and it makes the task of such an account easier, because the aliens, being merely stipulated, can easily be studied. :-)
I see, for instance, four rough but attractive accounts of assertion that work for the telepathic aliens:
- x asserts that s to y if and only if x intentionally brings it about that it seems to y that x informs it* that s
- x asserts that s to y if and only if x tries to bring it about that it seems to y that x informs it* that s
- x asserts that s to y if and only if x intentionally brings it about that it seems to y that x informs it* that s by means of a sufficiently properly functioning process whose telos is the bringing about of this mental state
- x asserts that s to y if and only if x tries to bring it about that it seems to y that x informs it* that s by means of a sufficiently properly process whose telos is the bringing about of this mental state.
(In 3 and 4, one needs to be clearer on what exactly is in the scope of the intention.)
And something like one of these might work for us, too.