Some people suggest that a reader does not need to know all the words that he encounters. Guessing words from context is a good strategy for learning unfamiliar English vocabulary.
The reality is that good readers do not need to guess, poor readers fail to guess.
This is a common misunderstanding of the topic shared by a lot of English teachers resulted from the ramifications of a renowned but error-prone work done in 1908 (Huey 1908) and its subsequent researches (e.g. Duffelmeryer 1984). The fallacy is so pervasive that many English teacher training materials still embrace this point of view.
The main error was that in the original and subsequent researches, the instruments used to measure the ability of a reader to guess the correct meaning of an unfamiliar word from the context were not derived from naturally occurring prose e.g. newspaper or novel. They were unrepresentative or specially contrived for the researches and were similar to a lot of ESL materials containing a lot of context clues that were not present in real life reading materials.
Style of a typical contrived context : He drank a ____ of coffee. _______ : the unfamiliar word.
Style of a typical naturally occurring prose : I like ham and _____ for breakfast.
In naturally occurring prose, authors tend to use words precisely and keep the redundancy minimal to increase the lexical richness of the writing.
Schatz & Baldwin (1986) derived a set of measuring instruments from naturally occurring prose and used it to investigate the effect of the presence of context in the ability of a reader to guess the correct meaning of unfamiliar words. The result was that the presence of context was only as good as no context.
According to the Transfer Feature Theory of Finn (1977-1978), a reader can guess the meaning of an unfamiliar word correct only if the contextual clues are already providing a lot of information about the sentence and the unfamiliar word. The unfamiliar word is a low-information word, usually also a high frequency word, which doesn’t provide much additional information to the sentence. The correct guess of the word neither adds much value to the understanding of the sentence nor skipping of the word causes any problem in the comprehension.
In contrast, those words that a user fails to guess are usually high-information words, and usually low frequency words. There are few clues to their identity that can be gathered from the words around. The correct understanding of these kinds of words has determining impact on the correct comprehension of the sentence.
Anyhow, no matter the guess is correct or not, the reader will never know whether his guesswork is accurate or not until he comes to know the meaning of the word at a later time, if he still remembers when he first encountered the word.
Most words that a secondary student needs to learn are content words from different academic subjects. Misunderstanding of these content words will have direct detrimental effect on the learning of the subject.
In another study, Gough, Alford, and Holley-Wilcox (1981) found that the false guessing outnumber the true by at least three to one.
Lastly, guessing can at best be considered as a reading strategy rather than a vocabulary acquisition strategy. Pressley, Levin and McDaniel (1987) found that even if a reader can guess the meaning of a word correctly, this doesn’t foster the retention of the word.