In two case studies of trilingual development in the home, it was not the home languages that were the strongest but the language of the respective daycare centres. This paper investigates, first, how well the trilingual children could separate their daycare language from their home languages. Then it explores the kinds of communicative interaction in the daycare setting that promote language development. Data were collected at Japanese daycare centres for a trilingual German-English-Japanese boy from ages 1;1 to 1;10 and for a trilingual Chinese-English-Japanese girl from ages 2;0 to 2;4. Both children demonstrated discourse separation by using more than 90% Japanese in the daycare environment. Notably, two recurring discourse patterns were found in the input--the use of gesture-supported speech and onomatopoeic expressions. Both types of input make communication more transparent for language-learning toddlers. This study of trilingual children in the daycare environment demonstrates that: (1) having fewer opportunities to communicate in multi-party conditions in daycare environments does not necessarily impede language development; and (2) receiving higher levels of caregiver than peer speech does not mean that peers have no role in supporting trilingual children's language development. (Contains 3 tables and 4 figures.)