Difficulty of expressing thoughts verbally Some people find it difficult to express their thoughts verbally. They may often feel that their words don't give their thoughts enough justice, and that their thoughts could've been verbalized better.


What can the causes for this be?
Can it be "cured" or alleviated, maybe by reading, and participating in conversations?
This is not a direct answer to the question, but a related construct that may be useful is alexithymia. 

Alexithymia is a personality construct describing relatively decreased ability to identify and express emotions. Psychometrically, the alexithymia construct has seen extensive use and undergone testing that by and large supported its validity (Bagby, Parker and Taylor, 1994a; Bagby, Parker and Taylor, 1994b). In clinical populations, the causes have been theorized to include anterior cingulate cortex and right hemispheric dysfunction, but the cognitive neuroscientific evidence is currently mixed (Zaidel, 2005). 

Unfortunately, I am not aware of any direct parallel for the inability to adequately express thoughts, nor of any direct treatments, and I was not able to find anything in the literature. Hopefully, the alexithymia construct may still be of some use in finding an answer. 

References


Bagby, R. M., Parker, J. D., &amp; Taylor, G. J. (1994). The twenty-item Toronto Alexithymia Scale—I. Item selection and cross-validation of the factor structure. Journal of psychosomatic research, 38(1), 23-32.
Bagby, R. M., Taylor, G. J., &amp; Parker, J. D. (1994). The twenty-item Toronto Alexithymia Scale—II. Convergent, discriminant, and concurrent validity. Journal of psychosomatic research, 38(1), 33-40.
Zaidel, G. T. E. (2005). Alexithymia, interhemispheric transfer, and right hemispheric specialization: a critical review. Psychother Psychosom, 74, 81-92.