Q. Why is the word salmon pronounced with a silent L? Even the word salmonella has an L that is pronounced. Other words that begin with sal- are almost always pronounced with an L.

A. The /l/ in salmon has never been pronounced. It is merely etymological. There are many other such common words in English, such as chalk or half. The word salmonella isn't actually derived from the word salmon but from an unrelated name, the veterinarian Dr. Daniel E. Salmon.

Q. The Online Dictionary says that now is a noun in the phrase "...been ill up to now," but that it is an adverb in in the phrase "come in now." In both examples now seems to mean the same thing. Also, M-W calls here a noun meaning "this place," and an adverb when used in the phrase "Come here." I can't see what the difference is!

A. The classification of words is sometimes much trickier than it seems. One might think that professional lexicographers would at the very least agree on parts of speech, but there are a surprising number of cases in which an argument can be made for a particular usage of a word fitting into more than one category. Usually it's the most common words, like now and here, that cause the trouble.

As we see it, now in "been ill up to now" is the object of the preposition "up to," and therefore is a noun. In "come in now," it's an adverb modifying the verb come. (In is also an adverb here.) I also interpret now as a noun in "He should have done it by now," with the word again being the object of a preposition, this time by. (The prepositional phrase "by now" is modifying the verb done and therefore is functioning adverbially.) The Oxford English Dictionary, it's interesting to note, hedges completely, covering this sense of now under a special section for phrases: "With prepositions, as by (also ere, for, or, till, unto, etc.) now."

Here can be construed similarly. As the object of a preposition – usually from – it's a noun: "I can see it from here." But when it modifies a verb, either on its own or after another adverb, it's an adverb: "Turn here." "The box is in/down here." "Come over here."