repeating verses

Question

Kavod HaRav- When singing songs at the Shabbat table, or when davening with a tune (like Aleinu or Aveinu Malkainu...), is it permitted to repeat verses? I've heard it's allowed because it's beautifying the davening or the Shabbat table, but it seems wrong that once one says HaShem's name, he/she repeats a verse! Thank you!!