<Tr> <Td> would </Td> <Td> informal, as in "We'd like to go ." </Td> </Tr> <Tr> <Td> will </Td> <Td> -'ll </Td> <Td> informal, as in "I'll call you later ." </Td> </Tr> <Tr> <Td> of </Td> <Td> o' / - a </Td> <Td> informal, as in "cup o' coffee," "barrel o' monkeys," "Land o' Goshen," "lots o' luck" </Td> </Tr> <Tr> <Td> ~ the </Td> <Td> ~ </Td> <Td> used mostly in o'clock, where it is mandatory in contemporary use </Td> </Tr>

When did contractions become part of the english language