Humans brain is an organ that consists of two hemispheres: left - linguistic and right - non-linguistic. And although it’s a very generalized statement,  it should be added that these hemispheres cooperate closely and do not work in isolation, today we are most interested in the fact that the left hemisphere is responsible for receiving and creating language, i.e. speech. In a word - it is dominant for the speech function.

Małgorzata Kostecka – speech therapist (30.03.2018)