A man was mentioned to the Prophet ﷺ who was being deceived in transactions. The Prophet ﷺ said to him, "When you make a transaction, say, 'No deception.'"So whenever he made a transaction, he would say, "No deception." He had a lisp in his speech.
حدثنا أبو سلمة أخبرنا سليمان بن بلال عن عبد الله بن دينار
ذكر للنبي ﷺ رجل يخدع في البيع فقال له من بايعت فقل لا خلابة فكان يقول إذا بايع لا خلابة وكان في لسانه رتة
Its isnad is sahih, and it is a longer version of 5271. Ratta, with the ra pronounced with damma, is described in Lisan as speaking hastily and lacking deliberateness, and it is also said to mean turning the lam into a ya. We have already mentioned, in the commentary on hadith 5036, the statement of Ibn Athir, "It occurs in one narration as 'la khiyaba,' with a ya, as though it were a lisp on the part of the narrator, who substituted a ya for the lam. This is the ratta, but in this case it was in the man himself, not in one of the narrators."