There are no commonly used words in English where the letter "o" is silent. However, there may be some words borrowed from other languages, like "doux" in French, where the "x" is pronounced instead of "ou".
The reason the letters "kn" are silent in English words is due to historical changes in pronunciation. The "k" used to be pronounced in words like "knight" and "knit" in Old English, but over time the pronunciation evolved and became silent. This is one of many examples of how the English language has undergone shifts in pronunciation throughout history.
Not sure which is the most prevalent, but here are some: the letter "g" which is silent when followed by an "n' at the beginning or end of words such as "gnash" and "gnome" and "benign" or resign". Not however when the syllables separate the letters, i.e., "dragnet". Another would be the silent "b" for words ending in "mb" like "bomb" "comb" Or the silent "c" in words / syllables beginning with "sc" as in "science" and "ascend" and "scissors". Seems like this might be the most frequent. And in American English, an "H" starting some words and secondary syllables, such as "honor" or "exhibit" or "exhaust" or "graham" Then there is the silent "k" when followed by "n" as in "knot, Knowledge, knives" Words ending in 'mn' -- silent 'n', like in "limn" "autumn" "condemn" Words with initial "wh" -- silent "H" -- "where, when, who" and with initial "wr" -- silent "w" -- as in "write" and 'wrench" Silent "t" for words ending in "stle" as in "castle" or "trestle"
The silent "g" in words like "gnarl" comes from the word's Old Norse origins. In some cases, the "g" used to be pronounced, but over time it became silent in English pronunciation.
Plain English is simple, straightforward, easily understood English,in other words the opposite of the English used by lawyers which uses long words, out-of-date words, technical words and Latin words.
Some examples of words with a silent "m" are mnemonic, subtle, and hymn.
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There is no definitive answer to this question, it is difficult to decide what is 'English', there are Latin words used in Law and French words used in cooking. However there is a dictionary know to contain 171,416 words in current use and 47,156 obsolete words. All in all there may be 250,000 words available in English.
They will usually give words that are not commonly used, have silent or double letters, and extended words for intimidation (such as unobstructiveness, they add the un- and -ness) See the related link for a long list of words used in spelling bees.
Two words borrowed from the Spanish language and used in English are "quesadilla" and "fiesta."
Some of the most commonly used words in the English language include "the", "people", "about", and "like". Other words include "time", "because", and "first".
The article "an" is used before "honest" because the pronunciation of the word begins with a vowel sound. This follows the rule that "an" is used before words starting with a vowel sound, while "a" is used before words starting with a consonant sound.