W. studies aspect and mood and their interrelation across different languages. Three moods (realis, irrealis, necessity) and three aspectual verb forms (neuter, perfective, imperfective) together make up a nine-cell matrix, the slots of which can be filled for any one language. Data from English, French, German, Kaingang (Brazil), Denya, Kom, Tikar, Bangando, Mofu, Daba (all Cameroon).