Q: Tarragon, dill, rosemary, and thyme are herbs. The “h” is silent in describing them generically. Ergo, does one say tarragon is an herb or tarragon is a herb? My Microsoft Office spell-checker is flagging the latter.
A: In the United States, the “h” in “herb” is silent. In Britain, it’s sounded. We say “an ’erb” while the British say “a herb.”
No matter which side of the Atlantic we hail from, we generally use the article “an” before a vowel sound (like a silent “h”) and “a” before a consonant sound (like a pronounced, or aspirated, “h”).
If you’re an American, give your spell-checker a pat on the back. If you’re a Brit, give it a good, swift kick. Spell-checkers can be useful (say, to point out typos or repeated words), but if you automatically make all the changes they suggest, your writing will be riddled with errors (often hilariously so).
PS: The American Heritage Dictionary of the English Language (4th ed.) has an interesting Usage Note on the “h” in “herb” and similar words that English has borrowed from French. Here it is, broken into paragraphs to make it more readable:
“The word herb, which can be pronounced with or without the (h), is one of a number of words borrowed into English from French. The ‘h’ sound had been lost in Latin and was not pronounced in French or the other Romance languages, which are descended from Latin, although it was retained in the spelling of some words.
“In both Old and Middle English, however, h was generally pronounced, as in the native English words happy and hot. Through the influence of spelling, then, the h came to be pronounced in most words borrowed from French, such as haste and hostel. In a few other words borrowed from French the h has remained silent, as in honor, honest, hour, and heir. And in another small group of French loan words, including herb, humble, human, and humor, the h may or may not be pronounced depending on the dialect of English.
“In British English, herb and its derivatives, such as herbaceous, herbal, herbicide, and herbivore, are pronounced with h. In American English, herb and herbal are more often pronounced without the h, while the opposite is true of herbaceous, herbicide, and herbivore, which are more often pronounced with the h.”
By the way, the “h”-less American pronunciation of “herb” is the original pronunciation of the word in Middle English, when it was usually spelled “erbe.” As the Oxford English Dictionary notes, “the h was mute until the 19th cent., and is still so treated by many.”