reduplication

(noun) repetition of the final words of a sentence or line at the beginning of the next. Synonyms: anadiplosis.

(noun) the syllable added in a reduplicated word form.

(noun) a word formed by or containing a repeated syllable or speech sound (usually at the beginning of the word).

(noun) the act of repeating over and again (or an instance thereof). Synonyms: reiteration.