Methods and apparatus to identify alternate language versions of media based on signature matching are disclosed. Example apparatus disclosed herein include a signature matcher to compare signatures in monitored data with reference signatures to determine signature match strengths associated with portions of the monitored data, the reference signatures associated with reference media assets. Disclosed example apparatus also include a data segmenter to divide the monitored data into first and second segments, the first segments including temporally adjacent portions of the monitored data having signature match strengths that satisfy a threshold, the second segments including temporally adjacent portions of the monitored data having signature match strengths that do not satisfy the threshold. Disclosed example apparatus further includes a trend determiner to determine, based on a pattern of the first and second segments, whether the monitored data is associated with an alternative language version of one of the reference media assets.