This study investigated how young children form passive sentences in English and Indonesian. When using the passive voice the grammar of English requires that a so-called passive form of the verb be used. In contrast to English, Indonesian passives are expressed without an auxiliary verb, by adding the prefix di- to the verb
The passive voice is very frequent in Indonesian, much more frequent than in English. In English the frequency is estimated at about 4-5% in the input to children, but in Indonesian it is estimated between 28-35%. We investigated whether children (ages 2;00-5;00) can comprehend passive clauses easily in both English and Indonesian. We predicted, that with the right comprehension methods passives in both English and Indonesian would be easily understood, undermining the maturational account. If comprehension is equivalent in both languages one can also argue against a frequency based analysis.