Why do I detect Slavic accents in people from Oporto and São Paulo when they speak English?

The Slavic accents you detect in people from Oporto and São Paulo when they speak English may stem from historical Immigration patterns and cultural influences in these regions. In Oporto, there may be a blend of linguistic influences due to migrations and the presence of Slavic communities. Similarly, São Paulo has a diverse population with significant Eastern European immigration, which can affect the way English is pronounced. These accents can result from the phonetic characteristics of their native languages influencing their English speech.