1. A method for language prediction of a social network post comprising: generating a social network graph which includes nodes connected by edges, some of the nodes being user nodes representing users of a social network, at least some of the users being authors of social network posts, and some of the nodes being social network post nodes representing social network posts of the authors, at least one of the social network post nodes being unlabeled, the edges of the graph being associated with respective weights; predicting language labels for the at least one unlabeled social network post node, including propagating language labels through the graph using label propagation as a function of the respective weights; and predicting a language of the social network post based on the predicted language labels generated for the social network post node representing that social network post, wherein at least one of the generating of the social network graph, propagating language labels, and predicting the language of the social network post is performed with a processor.