<Tr> <Td> first </Td> <Td> thirst </Td> <Td> ˈfɜː (r) st </Td> </Tr> <Tr> <Td> fissile </Td> <Td> thistle </Td> <Td> ˈfɪsəl </Td> <Td> Some accents pronounce fissile as / ˈfɪsaɪl / . </Td> </Tr> <Tr> <Td> for </Td> <Td> thaw </Td> <Td> ˈfɔː (r) </Td> <Td> Non-rhotic accents . </Td> </Tr> <Tr> <Td> for </Td> <Td> Thor </Td> <Td> ˈfɔː (r) </Td> </Tr>

Why do the english pronounce th as f