Definition of "soft-spoken"

[S]he was one of your ſoft ſpoken, canting, whining hypocrites, who with a truly jeſuitical art, could wreſt evil out of the moſt inoffenſive thought, word, look or action; […]

1765, Catherine Jemmat, The Memoirs of Mrs. Catherine Jemmat, Daughter of the Late Admiral Yeo, of Plymouth. Written by Herself, 2nd edition, volume I, London: Printed for the author, at Charing-Cross, page 145

With no great disparity between them in point of years, they were, in every other respect, as unlike and far removed from each other as two men could well be. The one was soft-spoken, delicately made, precise, and elegant; the other, a burly square-built man, negligently dressed, rough and abrupt in manner, stern, and, in his present mood, forbidding both in look and speech.

1841 February–November, Charles Dickens, “Barnaby Rudge”, in Master Humphrey’s Clock, volume II, London: Chapman & Hall, […], chapter 12, page 301

In fact, this educator, lawyer, editor, composer, author, poet, and diplomat [James Weldon Johnson] would become a sturdy fulcrum for black America's transition in 1916 from the softspoken conformity and accommodation of the Booker T. Washington era to a vigorous militant idealism that targeted no less than full equality.

1991, Gene M. Burnett, “Black Star out of Jacksonville: Native Son Achiever James Weldon Johnson was Lawyer, Educator, Composer, Author, Diplomat, and National Black Leader”, in Florida’s Past: People and Events that Shaped the State, volume 3, Sarasota, Fla.: Pineapple Press, section I (Achievers and Pioneers), pages 62–63

We were driving to the Tasikoki Wildlife Rescue Centre, south of Bitung, to meet with Harry Hilser, program manager for the nonprofit Selamatkan Yaki—which works to save Sulawesi's crested black macaques—and the rescue center's manager, Simon Purser, a soft-spoken Brit who seems to carry the weight of the world on his slim frame.

2017 March, Jennifer S. Holland, “For These Monkeys, It’s a Fight for Survival”, in National Geographic‎, archived from the original on 3 May 2017