The left side of the brain is generally dominant for language and other logical tasks. This side of the brain is also used for math or various calculations, according to the University of Washington. The left side of the brain also controls muscles on the right side of the body. Sensory information from the body’s right side crosses over to the left side of the brain.
The ability to form words primarily lies in the left hemisphere, states the National Institute of Neurological Disorders and Stroke. Both hemispheres are divided into sections, or lobes, which specialize in different functions. The Broca’s area, which is found on the left frontal lobe, enables thoughts to be transformed into words.
The left hemisphere of around 95 percent of right-handed individuals and 60 to 70 percent of left-handed persons is dominant for language, explains the University of Washington. The two specific areas of the brain that are important for language are named the Broca’s area and Wernicke’s area.
As most of the signals from the brain to the body and vice versa cross over when reaching the brain, both left and right hemispheres control the opposite side of the body, notes the NINDS. Thus, when the left hemisphere is damaged, the right part of the body is affected. For instance, a stroke in the left hemisphere usually leaves the right arm and leg paralyzed.