Sentence:  One difficulty attending <WSD>"memoriter</WSD>" speaking is, that the attention is likely to be concentrated upon words and periods rather than upon the whole subject, so that often on coming to the end of a sentence the speaker will have lost the thread of his argument, and there will be a total blank presented to his mind. 
Meaning of the word marked with <WSD> tags:  That is or has been recited from memory; that has been learned by heart.