Is it possible to raise your child trilingual?

Yes. However there are a couple of things to keep in mind. Parents should only talk to their children in their mother tongue. A language is not only a way to communicate, it transmits also tradition, culture, emotions, mindset and many other habits that are typical in a specific country. Parents should not mix languages as children need to learn that a specific person has to be addressed in a specific language, otherwise they learn that languages can be mixed. The passive skills are always bigger than the active language skills, don't give up too early! They will make use of their passive language skills at some point. It is easier to learn languages if you also listen to music, watch movies in different languages and have friends that speak those languages. Remember that every person is different. Even if you raise different kids the same way, some of them might learn languages easier than others. Languages are a gift that will always help you to understand other cultures, people and mindsets and expand your horizons.