Speakers are able to speak in synchrony to another speaker or to a recording of another speaker. The present research studied whether and, if yes, speakers change their speech rhythm when synchronizing to another speaker. We developed a measure (SRratio) which monitors on a scale between 0 and 1 whether the durational characteristics of a speaker’s synchronous speech are closer to his/her own read speech or closer to the characteristics of the speech of the speaker he/she is synchronizing to. Four speakers (synchronization speakers) synchronizing to twelve recorded sentences produced by four other speakers (target speakers) were studied. The durational characteristics we analyzed were %V and nPVI-v. Results for SRratio suggest that complex processes are going on with main effects for synchronization speakers and target speakers and interaction of the two factors.