A compound expression may contain several words without making a complete predication. What matters is whether it asserts something or merely identifies a referent.
غُلَامُ زَيْدٍ — Zayd's servant: a phrase expressing a relation.
غُلَامُ زَيْدٍ حَاضِرٌ — Zayd's servant is present: a full assertion.
The breadth of kalam at this point permits discussion of linguistic quality in composite expressions, including those that do not by themselves assert a complete proposition.