This paper investigates the acoustic correlates of word-level stress and phrase-level focus-related prominence in Mankiyali, a highly endangered Indo-Aryan language spoken in Northwest Pakistan that utilizes a weight-sensitive stress system. Of the acoustic properties measured (duration, f0, intensity, spectral tilt, and vowel quality), duration was the only feature found to robustly and consistently correlate with word-level stress across syllable types. In contrast, phrase-level focus-related prominence corresponded to an amplification of all five acoustic features measured. Given that vowel duration serves a vital role in preserving lexical contrast in Mankiyali, these findings present difficulties for a strong version of the Functional Load Hypothesis, which claims that acoustic properties bearing a high functional load in a language will not be used to mark prominence. In addition, results support an analysis of Mankiyali’s stress system as having five distinct levels of weight, a pattern which is extremely rare, if not unattested, elsewhere in the world’s languages.