Pleasant Speech Increases Learning

Anyone with a wise heart is called discerning,
and pleasant speech increases learning.

Insight is a fountain of life for its possessor,
but the discipline of fools is folly.

The heart of a wise person instructs his mouth;
it adds learning to his speech.

Pleasant words are a honeycomb:
sweet to the taste and health to the body.
-Proverbs 16:21-24

Learning here should be translated persuasiveness.
The wise man (not necessarily the clever one) will get known (a) for his discerning eye (AV: prudent) and (b) for his telling speech (21b, 23). Those who lack judgement or who talk above their hearers' heads need not pine for recognition; only for wisdom.
-Derek Kidner

The picture above is from the book, Mrs. Gladstone (1920)
Some text before the picture:
She was in the habit of reading aloud to her children in later years; Scotts novels were read in that way. The following little note written by Catherine is interesting for its words on Bishop Heber, a great friend of Lady Glynnes: I could not have been more than eight when Bishop Heber first visited Hawarden Castle, 1820 I believe, but words spoken of him by my Mother have not faded. In 1815 she had become a widow. It was natural at such a time of trial that inter-course such as was now offered should be of special value. For I recall the Bishops singular gifts, his greatness, his charm, his persuasiveness. So it was through her conversation afterwards that I can recall how comforting and precious it was to her. Then I remember the deep interest on hearing that he was to be Bishop of Calcutta, and the awe and sadness with which we received the tidings of his death. Long afterwards Mrs. Gladstone told her