Previous research has shown that adults can implicitly learn segmental phonotactic constraints, but the implicit learnability of prosodic features like lexical stress and lexical tone remains unclear, especially given the variability in results among learners from different language backgrounds. To address this, our study examined the implicit learning of non-native tone-segment associations in adults, both with and without tonal language backgrounds, specifically Mandarin and English. Initially, participants were evaluated on their ability to acoustically and lexically distinguish tones. Subsequently, they were unconsciously exposed to tone-segment connections in pseudowords, followed by tests to assess their memorization and generalization skills. We also measured their awareness of the tonotactic rules through confidence ratings and structural knowledge attributions.