One of the things that irritates me most when I’m reading, whether it’s a novel, a newspaper article, or a mathematics paper, is the misplaced “only.”
If you write “Here we only calculate the position of two vertices” you probably mean “Here we calculate the position of only two vertices.”
The word “only” is there to emphasize something, and it should be as close as possible to what you want to emphasize to be effective and to convey the desired meaning.
As described in Mathematical Writing (MAA, 1989), newspaper copy editor Rosalie Stemer gives the following sequence of examples to illustrate how the placement of “only” can affect the meaning of the sentence “I hit him in the eye yesterday.”
Only I hit him in the eye yesterday.
I only hit him in the eye yesterday.
I hit only him in the eye yesterday.
I hit him only in the eye yesterday.
I hit him in only the eye yesterday.
I hit him in the only eye yesterday.
I hit him in the eye only yesterday.
I hit him in the eye yesterday only.
Each sentence has a distinct flavor, depending on the placement of “only.” Its placement subtly (sometimes drastically) changes the meaning. Sloppiness in its placement can lead to ambiguity.
Nonetheless, examples of the misplaced “only” abound in the literature. The most common fault is placing “only” in front of the verb rather than in front of the object, as illustrated in the first example, above.
Here’s one from a newspaper. The sentence begins “when something only happens four times in eight decades.” It would be more effective if it were written as “when something happens only four times in eight decades” (unless the author did intend to stress the “happens” part and not the number of times).
H.W. Fowler in A Dictionary of Modern English Usage (Oxford University Press, 1965) complains that pedants take this too far. He offers this advice: “. . . there is an orthodox position for the adverb, easily determined in case of need; to choose another position that may spoil or obscure the meaning is bad; but a change of position that has no such effect except technically is not only justified by historical and colloquial usage but often demanded by rhetorical needs.”
Fowler sees nothing particularly wrong with “He only died a week ago.” “It is the order that most people have always used and still use,” he noted, and that, “the risk of misunderstanding being chimerical, it is not worth while to depart from the natural.”
At the same time, avoiding ambiguity matters. “If any words in a sentence are misplaced, the meaning conveyed may not be the meaning intended,” Robert Barrass advises in Scientists Must Write (Routledge, 2002). “So, ensure that what you write does express precisely what you mean. Do not expect readers to waste their time trying to guess what you probably meant.”
How would you decipher the following: “In this book those points of grammar only are discussed which will help you to ensure accuracy. . . ”?—I. Peterson
The words “likely” and “mostly” also fall in the same category as “only”. When these errors occur in books, we conveniently attribute it to printing mistakes. I have always wondered how sometimes even when these words are misplaced, they are understood correctly. Do we get used to the incorrect usage and our brain internally makes the correction?
I think Peterson means “only those points…” but then, who knows? I appreciate Latin in this case where the inflected forms of words means that word order is irrelevant to the meaning of a sentence.