I met a lady the other day who was born in Russia. She moved to France with her family and had most of her upper education there. Later she moved with her family to the USA.
She speaks fluent Russian, French and English. I asked her if she thinks in English.
Her answer was this.
I commonly think in English - most of the time actually. The two main exceptions are when I am doing math of which at that time I think in French since my math training was mainly in France,
The second exception is when I get mad.
------ when I get mad -------- I think in Russian.
I think some of you can relate to that LOL