One of our Year 1 students explains perfectly, why it makes sense for her to use her mother tongue (French) sometimes for writing while she is building up her English.
Q: Why did you decide to write it in French?
A: Because I didn't know how to write these word in English and I choose to do in French.
Q: How did you feel when you wrote it in French?
A: Happy!
Q: Why did you feel happy?
A: Because it was my language, French!
So from the mouths of our students... Translanguaging makes you happy!