A cantor's craft is inseparable from nusach, the traditional melodic system that governs how the liturgy is chanted differently depending on the specific service, the season, and the community's own regional heritage, so that the same words of a prayer may be sung to markedly different, tradition specific melodies at a weekday service, a Sabbath service, and the High Holy Days, and again differently between Ashkenazi and Sephardi congregations.
Learning nusach thoroughly, alongside Hebrew liturgical text, vocal technique, and often Jewish law relevant to the service, is the core of formal cantorial training, historically transmitted through apprenticeship to an established hazzan and, since the twentieth century, increasingly through dedicated cantorial schools attached to rabbinical seminaries across the major American and some European Jewish denominations.
Reform and Conservative Judaism generally require formal cantorial school investiture for a hazzan serving in that capacity, while many Orthodox congregations continue to rely more on a candidate's demonstrated skill, reputation, and communal recognition than on a seminary credential, reflecting a broader Orthodox preference for informal, community based recognition of religious roles over centralized institutional certification.