#spectrogram reading

once again i ask myself what logic gramle applies when transcribing the vowels of unstressed syllables. i'm still not sure how to segment the first three segments. i correctly read the cues of a low f3 at the beginning as rounding, but it was hard to see where the f3 went after the first 0.15 seconds, though i luckily guessed that it increases (so the next vowel is not rounded). if anyone knows how to tell apart any of the sonorant consonants, lmk. also apparently english has not only final obstruent devoicing but also fricative devoicing too?