But the pauses are semantic in a way. Those concepts cannot be well separated. Not a linguist, but I can tell pauses are used by speakers and listeners for a variety of reasons, linked with both semantics and delivery -- to separate parts, to give and demarcate "processing time" for speakers and listeners, to create and satisfy expectation, etc. The cadence of speech is semantic (though its semantics are not of a simple propositional logic type).