The Mishna (52b) records that there were different traditions in different parts of Israel with regard to ketuba. Specifically, in Jerusalem and the Galilee the widow was permitted to continue living in her husband’s home, supported by the orphans, while in Judea and the southern part of Israel the ketuba allowed the orphans to pay her what was owed to her and force her out of her home. The Talmud Yerushalmi summed up the argument by saying that the people of Judea worried more about their money than their honor, while the people of the Galilee worried more about their honor than their money.
Our Gemara relates that this difference of opinion existed in Babylon as well, where Rav accepted the tradition of the community in Judea and Shmuel accepted the tradition of the people of the Galilee and Jerusalem. Based on this, the community of Bavel generally followed Rav, while the community of Neharde’a followed Shmuel.
A young woman from Mehoza who was married to a man from Neharde’a came before Rav Nahman to discuss this very situation. Hearing her accent, Rav Nahman suggested that she must fall into the category of people who follow Rav and the tradition of the people of Yehuda. When it was clarified, however, that her husband hailed from Neharde’a, he changed his ruling, explaining that the community of Neharde’a followed the position of Shmuel, and that this extended to all areas where kaba d’Neharde’a was accepted.
The kaba d’Neharde’a was the Neharde’a standard weight measure. For many years – and in some countries, to this day – within a given country one could find a variety of local weights and measures. Sometimes one would find different standards of measures even in two cities that were in close proximity to one another. Oftentimes, these local measures pointed to ancient independent areas, like cities or districts. The Jewish community in Babylon was broken into a number of different districts, which, during the times of the ge’onim had clear geographic and legal boundaries. These distinct districts were obvious, for example, from different word usage and accents, and they followed different traditions – like accepting the rulings of one Sage over another.
(For a more comprehensive look at units of measurement, refer to the Jewish Encyclopedia.)