Languages are often categorized as having either predictable (fixed or quantity-sensitive) or non-predictable stress. Despite their name, fixed stress languages may have exceptions, so in fact, their stress does not always appear in the same position. Since predictability has been shown to affect certain speech phenomena, with additional or redundant acoustic cues being provided when the linguistic content is less predictable (e.g., Smooth Signal Redundancy Hypothesis), we investigate whether, and to what extent, the predictability of stress position affects the manifestation of stress in different languages. We examine the acoustic properties of stress in three languages classified as having fixed stress (Turkish, French, Armenian), with exceptions, and in one language with non-predictable-stress, Brazilian Portuguese. Specifically, we compare the manifestation of stress in the canonical stress (typically "fixed") position with its manifestation in the noncanonical (exceptional) position, where it would potentially be less predictable. We also compare these patterns with the manifestation of stress in Portuguese, in both the "default" penultimate and the less common final position. Our results show that stress is manifested quite similarly in canonical and non-canonical positions in the "fixed" stress languages and stress is most clearly produced when it is least predictable.