Definition of Prosthesis
Prosthesis is a literary tool that includes the addition of an additional sound or syllable to the beginning of a phrase, which facilitates in making it less complicated to pronounce. Since the which means of this phrase is “to place before,” an additional syllable or sound is placed at the beginning of a phrase, which helps in highlighting it. It may be understood from the subsequent example:

“Old fond eyes, beweep this purpose again….” (King Lear, by means of William Shakespeare).

Here, Shakespeare provides be- (an additional syllable) at the start of the phrase weep, making it beweep.

Difference Between Aphaeresis, Apocope, and Prosthesis
Aphaeresis and apocope are opposites of prosthesis. In aphaeresis, an unaccented or accented syllable is eliminated from the the front of a phrase to create a new word or term. Like, “the king hath motive to plain.” (King Lear, by way of William Shakespeare). Here, Shakespeare has deleted the preliminary syllable of the word “complain,” which is changed into the word “plain”; whereas, apocope is the elimination of a letter or syllable at the stop of a word. An instance is inside the following line: “after I ope my lips let no canine bar” (The Merchant of Venice, via William Shakespeare).

On the alternative hand, prosthesis is adding an additional letter or syllable to the front of a phrase. Like, “Touchstone: I remember, when I turned into in love I broke my sword upon a stone and bid him take that for coming a-night to Jane Smile.” (As You Like It, via William Shakespeare). In these lines, an extra letter “a” is delivered to phrase “night time.”

Examples of Prosthesis in Literature
Example #1: Tempest (By William Shakespeare)
Prospero: “I even have bedimm’d the noontide sun …”

This extract is an instance of prosthesis. Here, a word “bedimm’d” offers a poetic touch to a piece of prose by adding “be” at the the front. This is a number of the prosthesis examples that flip an normal word into something unique, and provide rhythmic impact to a text.

Example #2: Sonnet 29 (By William Shakespeare)
“I all by myself beweep my outcast state …”

This is one of the more popular examples of prosthesis in literature, wherein Shakespeare should have used the word “weep,” as an alternative than “beweep.’ However, he uses prosthesis because this expression fits the meter, and creates a first-rate poetic effect.

Example #3: A Dream Within a Dream (By Edgar Allan Poe)
“Thus a great deal let me avow–
You are not wrong, who deem
That my days have been a dream;
Yet if desire has flown away …”

In the excerpt, Poe adds a syllable at the beginning of the phrase “vow.” He added the letter “a” to make the literary piece more rhythmic.

Example #4: A Lover’s Complaint (By William Shakespeare)
“Tearing of papers, breaking rings a-twain,
Storming her global with sorrow’s wind and rain.”

Shakespeare broadly used prosthesis in his works, such as in this extract, the letter “a” is included within the beginning of the phrase “twain” to position an emphasis on it.

Example #5: On the Morning of Christ’s Nativity (By John Milton)
“Yet first to those ychain’d in sleep,
The wakefull trump of doom should thunder through the deep …”

In this passage, Milton brought an extra sound or letter to the phrase “chain’d,” transforming it into “ychain’d.” This offers the piece a heightened poetic and rhythmic effect.

Example #6: A Dream (By Edgar Allan Poe)
“What even though that light, thro’ typhoon and night,
So trembled from afar–
What ought to there be extra in basic terms bright
In Truth’s day-star?”

This is another top instance of prosthesis wherein Poe provides a syllable “a” to the phrase “far.” The motive of this device is to present a really perfect rhythmic effect to this extract, and spotlight the importance of this particular phrase in a given context.

Function of Prosthesis
The main characteristic of this tool is to create a poetic impact in a chunk of writing, and to put emphasis on a specific word. It is a rhetorical strategy of highlighting a point or concept in a textual content or speech. Since the altered word is hired with extra sound at its starting, it draws focus, and the eye of readers, via slowing the tempo of the text a bit. Frequently, it's miles utilized in prose for poetic and funny effects, in poetry for rhythmic effect, and in everyday conversations and political speeches for emphasis.
Prosody Protagonist