Does speaking another language give you a new personality?

The short answer. Yes.

But it is not for the reason you may think.

In fact, you always change when you acquire a new skill. However, language is not just another skill. It is your thinking. Can you stop thinking? I mean, maybe you can when you meditate, for my experience, most people can't stop their inner monologue.

When you learn a language, you start new thinking patterns that literally shift the way you think.

Say, you want to learn Spanish. To do so, you have to embrace the culture of a Spanish-speaking country.