What is an alien phonology?
An alien phonology is a system of sounds — and perhaps other, non-vocal signals — for a language designed to be used by beings that are not human. It is designed to take advantage of a non-human anatomy, and will often use mechanisms of sound/signal production that would be convenient for the beings the language is made for, but are either inconvenient or impossible for humans.
What might an alien phonology have in it
An alien phonology would contain any phoneme (sound that is seen as being different form the other sounds) that would be easy for the alien to use. It's not too hard to imagine one, without even leaving Earth.
- Plates that make noise when they glide over one another.
- Used by many insects, chirp chirp!
- Colour changes.
- Many octopuses can change colour fast enough to use colour phonemically (to distinguish words form one another).
- No vocal cords.
- Birds have no vocal cords. Instead, they have a different kind of vocal organ called a syrinx.
- Two air streams
- Some kinds of birds use two air streams when they sing. (Mentioned here.)
- Non-aerial sound transmission
- There is evidence that pachyderms can send and receive sounds through the ground.
- This could be useful for a place where there is little air.
- Flashing lights
- Some species of deep water fish communicate warning signals with pockets of bio-luminescent bacteria that they can cover and reveal alternately.
Any and all methods of noise production and such can be used as phonemic signals, just because red is not phonemic to humans does not mean it isn't for octopi. Just because the smell of sulfur doesn't make an English word an adverb, doesn't mean it can't for an alien.
Alien language should be built around alien anatomy, I suggest that you figure out how they look, how would they make their sounds? what would be the most effective method of communication in their environment, would sound be used at all?
How do they think, who says they use verbs and nouns? I once read an article about a language that was so context-dependent that there was a play that was simply the same word ~6,000 times, with no rhythm or stress changes, but the fact that each word had been preceded by the same word changed its meaning.
Throw away traditional thinking when you work with aliens, they are after all, alien. When you're working with aliens, anything goes.