NET
29 You must let no unwholesome word come out of your mouth, but only what is beneficial for the building up of the one in need, that it would give grace to those who hear.
Darby
29 Let no corrupt word go out of your mouth, but if [there be] any good one for needful edification, that it may give grace to those that hear [it].
KJV
29 Let no corrupt communication proceed out of your mouth, but that which is good to the use of edifying, that it may minister grace unto the hearers.