Open round | 10 points | 49.41% | Problem statement | Official solution | Tags: Phonology
Stress usually depends on both the position and the type of the syllable. Here, among the 7 words given, we have:
And the secondary stress, if it exists, is always the second syllable after the primary one. Short words don't have secondary stress. So the only remaining question is how we choose between 3rd and 2nd for primary stress. Usually, the stress shifts because the default position cannot be stressed, or something else attracts stress.
If it's because the default position cannot be stressed: let's see what each word's second and third syllables are.
Unfortunately, there does not exist a clear complementary distribution in either the vowels or the consonants. So we can rule out this possibility.
If it's because something else attracts stress, we look for the context of the stress—i.e., the syllables around P. We immediately notice that for the second group, all syllables before P contain a long vowel, while in the first group, no syllable contains a long vowel. So the hypothesis is that the long vowel attracts stress, which by default is the 3rd syllable.
Following this: