Green’s Dictionary of Slang

a horseracing tip; esp. in phrs. get the speech, to receive a tip; give the speech, to pass on information.

1873

Sl. Dict. 303: Speech, a tip or wrinkle on any subject. On the turf a man will wait, before investing on a horse, until he ‘gets the speech,’ as to whether it is going to try, or whether it has a good chance. To ‘give the speech,’ is to communicate any special information of a private nature.