Do not use harmful words, but only helpful words, the kind that build up and provide what is needed, so that what you say will do good to those who hear you. (Ephesians 4:29 GoodNewsTranslation)
I looked at this verse in several translations:
Let no foul or polluting language, nor evil word nor unwholesome or worthless talk [ever] come out of your mouth, but only such [speech] as is good and beneficial to the spiritual progress of others, as is fitting to the need and the occasion, that it may be a blessing and give grace (God’s favor) to those who hear it. (Ephesians 4:29 AMP)
Don’t use foul or abusive language. Let everything you say be good and helpful, so that your words will be an encouragement to those who hear them. (Ephesians 4:29 NLT)
Let no corrupt word proceed out of your mouth, but what is good for necessary edification, that it may impart grace to the hearers. (Ephesians 4:29 NKJV)
Watch the way you talk. Let nothing foul or dirty come out of your mouth. Say only what helps, each word a gift. (Ephesians 4:29 MSG)
Each translation says the same thing. It doesn't seem to be just a suggestion and it is a "hard pill to swallow." Every word? I am convicted.
We are ambassadors for Christ, as though God were pleading through us: we implore you on Christ's behalf, be reconciled to God. For He made Him who knew no sin to be sin for us, that we might become the righteousness of God in Him (2 Corinthians 5:20-21).