The impact of surgical treatment for tongue cancer is traditionally assessed with vowel formant metrics from read speech or sustained vowels. However, isolated speech might not fully reflect a speaker’s typical speech. Here, we assessed the effect of speaking style (read vs. semi-spontaneous) on vowel acoustics of individuals preand post-surgery for tongue cancer. Eight individuals (3 females and 5 males) were recorded preand approximately six months post-surgery. We calculated the articulatory-acoustic vowel space (AAVS) during read speech (sentences) and semi-spontaneous speech (picture description). Results showed that the AAVS did not differ significantly preand post-surgery. Picture descriptions yielded a significantly smaller AAVS compared to the reading task, which was consistent preand post-surgery. Our findings suggest that both read and semi-spontaneous speech styles would be suitable to quantify the impact of surgical intervention for tongue cancer on vowel acoustics.