Babylonian Talmud, Tractate Shabbat, p. 113a
1 א
תלמוד בבלי מסכת שבת דף קיג עמוד א
2 ב
ודבר דבר - שלא יהא דבורך של שבת כדבורך של חול. דבור - אסור, הרהור - מותר.
'Nor speaking your own words:' that your speech [conversation] on the Sabbath should not be like your speech on weekdays. 'Speaking': speech is forbidden, but thought [about mundane matters] is permitted. [Soncino Translation]
3 ג

Suggested Discussion Questions:

According to this, how do you think a person should speak on Shabbat?

4 ד
Time Period: Rabbinic (Maccabees through the Talmud)