Spoken English uses ordinal (first, fifth, etc.), while written uses cardinal numbers (one, five, etc.). This is true, even though if I am reading a date written as a cardinal number (June 1, 1950), I would say it as an ordinal ("June first, nineteen fifty"). You can say a date as a cardinal number and you may also write a date as an ordinal, but that is usually not the case.

1st, 2nd, 3rd, etc....