I disagree. There's a subtle difference between breathing cadence and inflection, and a completely monotempo monotonal string of sounds.
Seems more productive (and enlightening to all) than the agree/disagree dialogue here.
The best way to see this is to try listening to a language you do not understand, and try to identify word boundries.
Indeed, the paper I link argues that some phonetic cue must exist because babies can recognise word boundries.
[1] https://www.sissa.it/cns/Articles/94_doInfPerceiveWordB.pdf
A monotonal, monotempo sound would not be able to make that difference audible