Sentence:  [...] in Athenaeum called him "an enthusiast," which almost goes without saying, but went on to say that his book is valuable inasmuch as it does "do good, as it teaches many overlooked (I [Barnes] say little known) points of <WSD>speechlore</WSD>. 
Meaning of the word marked with <WSD> tags:  The science, study, or knowledge of language or speech; linguistics.