Formant dynamics are believed to reflect the characteristic articulatory behavior of a speaker. The present study aims to explore individual articulatory behaviors when producing American English /æ/ and /ɑ/. The two vowels differ in the degree of inherent spectral change, a property believed to carry information about vowel-phoneme identity, which may be reflected in the articulatory movements. We measured first and second formants together with tongue blade and dorsum trajectories from 20 speakers producing 330 words in citation forms. Using the network analysis, the relationships between acoustic and kinematic variables were revealed. In particular, between-speaker articulatory behaviors were most dissimilar in /ɑ/ which requires less inherent spectral change. Moreover, when networks of speakers with similar formant patterns were compared, it was revealed that their articulatory behaviors also shared similarities, although they seemed to be organized in characteristic ways. These findings contribute to our understanding of the complex interaction between articulatory variables and the acoustic outcome.