For social creatures, the Strondovarians don’t have much in the way of facial features. Although a human may find Strondos to be cold and unemotional in many ways, they do in fact have emotions and, even without eyebrows to furrow or lips to curl, they can get their feelings across to others non-verbally.
Here, Nibnassin gives some examples of body posture and what emotion it may be revealing:
The upper arms of a Strondo are the biggest indicators. These limbs (they call them “Thast”) tend to droop when a Strondo is relaxed, often getting tucked behind their back when most comfortable. Contrary to that, if a Strondo is raising their Thast, you can be sure they’re trying to be imposing, and since they can swing a Thast in a powerful blow, they are pretty imposing.
Given that a significant part of a Strondo’s auditory sense organs are located behind their mouth, it is appropriate that the Strondo word for their lipless mouth hole is “Hear”. Though they only close their Hear tightly when eating, if they are especially interested in listening to something, they will open it wider to let more sound into the mouth cavity (which they call “Aaruo”) that serves as an echo chamber for the sound taken in.
The lower set of arms for a Strondo (the “Thae”) are more commonly used for finer manipulation, so if a Strondo has raised them, it is apparent that they are ready to engage in activities that require a more active role on their part. When they raise them, they’re ready to think and act in a less blunt way then with the Thast.
So that’s the basics you’d need to know to get the basic idea of how a Strondo is feeling. There are other little things they do (like shaking a single Thae to indicate impatience, or curling limbs inward to indicate feeling tense), but among Strondos, if you really want to catch their meaning you need to listen to what they’re saying.