1 Abstract The present thesis is concerned with the study of creaky voice and its communicative functions in audio-visual presentation of a brand. This study analyzes nineteen videos that were part of the Sign On campaign produced by Greenpeace in 2009. The main purpose of this thesis is to measure the level of creaky voice in communicative functions. The communicative functions presented in this study are based on the model of Roman Jakobson (1960) and some new functions are proposed as addition to the model. One of the predictions of this thesis is that functions that are emotionally loaded will be comparatively more creaky and this prediction is partially met. Secondly, it was expected to see the same order of the communicative functions based on their level of creakiness among different groups of speakers. This expectation was not met and the possible reasons for the findings are discussed. This thesis uses only acoustic measurements for the comparison of the communicative functions based on their levels of creaky voice. Finally, this thesis discusses the possibilities and current limitations of acoustic methods used for detection of creaky phonation. Keywords: creaky voice, vocal fry, laryngealization, communicative functions, F0, HNR, H1-H2, antimode