Then -- The Greek word for "then" means "at this time" or "then." With the subjective negative, the sense is "not when."

the   -- The word "the" is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more.

master ,  - The word translated as "master " also means "master," in the sense of owning slaves, which is the case here.

missing "of his"  -- (MW) The untranslated word "his" is the Greek word commonly translated as third-person pronouns in English.  This pronoun follows the noun so "of his.

called  - (CW, WF) The verb translated as "after he had called" means "call upon" or "summon, but it has the specific meaning to "cite or summon into court." It is in the form of an adjective, "summoning," referring to the lord or master. In Matthew 18:29, it was used from one servant to another as "called out." Here the sense is "summoned" because it is the king. It is not the simple word "called."

the servant in -- (IP) There is nothing that can be translated as "the servant in" in the Greek source.

missing "him"  -- (MW) The untranslated word "him" is the Greek word commonly translated as third-person pronouns in English. 

You -- This is added to indicate that the following word is in the form of address, using it as a term to identify someone.

wicked -- The word translated as "wicked" means "second-rate" or "worthless." It doesn't have a sense of malevolence that our word "evil" does. This article explores its meaning in more detail.

servant, -- The noun translated as "servant" means "slave." It is translated as "servant" to update the Bible.

he -- This is from the third-person, singular form of the verb.

said  - (WT) The "said" is the common word meaning "to say" and "to speak." It is the word Christ uses to refer to himself speaking. It is the present tense not the past. Until now, this story has been in a tense that is usually translated as the past.

missing "to him"  -- (MW) The untranslated word "him" is the Greek word commonly translated as third-person pronouns in English. 

I -- This is from the first-person, singular form of the verb.

canceled -- (WW) The word translated as "canceled " primarily means "to let go" or "to send away." This same word is usually translated as "leave," "forgive," "suffer," and "let" in the New Testament. See this article for more. It has the sense of leaving something alone and letting it drop. In this section, it refers to letting go of debts.

all  - The word translated as "all " means "all," "the whole," "every," and similar ideas. It is in the possessive case modifying "debt." So, a "debt of everything." It refers as much to the size of the debt as to how much was forgiven.

that - The word translated as "those" is an adjective that highlights its noun as being in a specific place or time from a word that means "there."

"missing "the"  -- (MW) The untranslated word is the Greek definite article, which usually precedes a noun and, without a noun, takes the meaning of "the one." The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," "those"). See this article for more. 

debt, -- The Greek word translated as "debt" is a noun that means "debt." Jesus used four different nouns and two verbs to describe "debt," almost all are related (except one), different forms of the same root. This is the simplest from the root.

of -- (WW) This word "for" comes from the dative case of the following word that requires the addition of a preposition in English. The most common is a "to" for the English indirect object. "Of" is from another word form.

yours --(WF)  The word for "yours" is the indirect object form of the singular, second-person pronoun.  It is not a possessive form and does not modify.

because  - (CW) "Because" is a word that means "since," "after that," and "when." It is interesting because it is not the word that Christ usually uses for "because." It is a word that Christ uses nowhere else, which is even more interesting.

thou -- This is from the second-person, singular form of the verb.

begged -- (WW) "Begged " is the same word translated above as "after he had called." which means "call to," "call in," "send for," "invite," "summon," "address," "demand," "exhort," and "encouraged." A lot of these meanings work.

me -- "Me" is the regular first-person pronoun in Greek as the object of the verb or preposition.

to  - -- This object is added and not in the Greek source.   In Greek, objects are not repeated after each verb because they are implied by their first occurrence.