Definition of "kerbstone"

You see this creature with her kerbstone English: the English that will keep her in the gutter to the end of her days. Well, sir, in three months I could pass that girl off as a duchess at an ambassador’s garden party.

1912, George Bernard Shaw, “Act I”, in Pygmalion‎

Gabriel often saw him on the streets, playing on the curbstone with other boys his age.

1953, James Baldwin, Go Tell It on the Mountain, New York, N.Y.: Knopf, part 2 (The Prayers of the Saints)