I did my therapy in English (my first language), but I found it easier to express some feelings in French (second language). English is 'me', so
saying things in French seemed less threatening somehow. I would write out my feelings in French and read them to my therapist (who didn't understand), and it was helpful. Eventually I could express myself in English and didn't need the French anymore.

Could you try something like that? Or if you're in a bigger UK city, could you look for someone who speaks Japanese?