In English , a colon may be followed by text with either a capital letter or by a lower-case letter , depending on usage : where speech follows , a capital letter is used ; where an acronym or proper noun follows , a capital is used ; otherwise a lower-case letter is used . However , in American English a colon may be followed either by a capital letter or by a lower-case letter , depending on usage : where direct speech follows , a capital letter is used ; where an acronym or proper noun follows , a capital is used ; otherwise , a lower-case letter is used .