I thought that this was a very interesting interview with a bilingual teacher in Finland about trying to integrate a different language (Swedish) into her monolingual class; http://www.tandfonline.com/doi/full/10.1080/09500782.2015.1009092
I agree with the teacher that you could use songs and dances to initially settle them into the new language, but then the foreign language should be integrated more into everyday class life. For example, on my placement class, the lunch register was asked and answered in French. I know a teacher who greets and asks her class how they are every day in Spanish. Teachers could start off like this, by slowly integrating it into the classroom, seeing how pupils are responding, and then building upon that. This also highlights the fact that it can be done through dialogue; children don’t always need to be handed a worksheet to translate as this can get very monotone.
It is important that teachers don’t force the language upon their class, the teacher in the research said she would accept a response in either Swedish or Finnish. This gives the children the option, and would hopefully prevent them from resisting/ getting bored or annoyed at learning the language.
The teacher set realistic, achievable goals; to familiarise the class with Swedish, taking the pressure off the children to perform well in a test. When she felt she had achieved this goal with them, she built upon that. In a primary class, you could agree on set goals with them so that the pupils feel responsible for their learning and have a clear view of what they are working towards.