This paper presents an investigation of acoustic-prosodic alignment in conversational speech and its relationship to functional inter-speaker alignment. While most previous research studied global alignment over whole conversations between strangers, the focus of this paper is on alignment between friends, partners and colleagues as a more local phenomenon related to affiliation and preference structure. Based on 359 turn-pairs from assessment sequences, we analyzed three prosodic matching features between adjacent turns in logistic and linear regression models. We found that disagreements tend to be produced with less F0 span matching than agreements and with less F0 median matching in some parts of the conversation. Preferred responses were more likely to be marked by higher F0 median matching than dispreferred responses. These results indicate that different aspects of functional inter-speaker alignment are reflected in matching along distinct acoustic-prosodic features.