well, let's see..

lethologica - the inability to remember the right word

anomia - a difficulty in finding the right words for objects or the inability to remember names

paramnesia - a condition in which the proper meaning of words cannot be remembered

aphasia - partial or total loss of the ability to articulate ideas or comprehend spoken or written language, resulting from brain damage due to injury or disease. Also called logagnosia, logamnesia, logasthenia

aphrasia - inability to speak, or to make intelligible phrases

I may, however, be suffering from loganamnosis..