Why then didn’t you put my money on deposit, so that when I came back, I could have collected it with interest?’

Why -- The word translated as "Where-" means primarily means primarily "anything" or "anyone," but Jesus often uses it to start a question so it means "who", "what","where", or even "why". 

fore -- missing "by"  -- (MW) The untranslated word The word translated as "-fore " means "through," in the midst of," or "by (a cause)."

then -- (WW) The Greek word translated as "then" is used as the conjunction "and", but it also is used to add emphasis ("also"). This word doesn't mean "then."  

gavest -- The verb translated as "gavest ...though" means "to give", "to grant", "to hand over", "appoint", "establish," and "to describe." It is almost always translated as some form of "give."

not -- The Greek word translated as "not" is the Greek negative used to deny objective facts, not opinions. It makes a negative statement of fact. Adding "really" to the sentence captures the same idea.

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

my -- "My" is the first-person possessive singular pronoun.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article," the," which usually precedes a noun or changes the word it precedes (adjective, infinitive, participle, etc.) to act like a noun. The Greek article is much closer to our demonstrative pronouns ("this," "that," "these," and "those"). See this article for more. 

money -- The word translated as "money" is an uncommon word for Jesus. It means "money" in the sense we use the term "cash," referring to the actual metal "silver."

into -- The word translated as "into " means "on", "over", "upon", "against", "before", "after", "during", "by" or "on." The sense is "on", which makes sense because of the meaning of the next word.

the -- (IW) This word is not in the Greek source.

bank -- (CW) The word translated as "bank" is uncommon and has the primary meaning of "table" or "counter". which originally meant "table" from the "tables" or "counters" of money-changers. However, it is not the Greek word used elsewhere in the NT translated as "money-changers." This word is used because it is a pun, since the word for "bank" also means the grinding surface of teeth and the lower mill stone which grinds grain. So in a sense the "grinders" are "bankers". This word doesn't precisely mean "bank." 

that at my --- (WW) This is from "and I" a contraction of the conjunction "and" and the first person pronoun, "I/me."  The "me" is an indirect object, usually translated as "to me. It appears below.   The "me" is an direct object. It appears below. This "I" is a subject.When it has no verb, the verb "is" or the previous verb is assumed. When the subject of the sentence is part of the verb, this pronoun's accentuates who is speaking "I." Saying "I myself" captures this feeling in English. This word doesn't mean "that at my."  

missing "myself" -- (MW)  The subject pronoun repeats the information in the verb so it should be repeated in English like "I myself."   

coming  -- The word translated as "coming" primarily means "to start out" but Christ usually uses it to mean "come" but not always. It indicates movement, especially its beginning, without indicating a direction toward or away from anything, so it works either as "start," "come," or "go," but it is more like our phrase "being underway." Our English word "show up" captures both the "start" and "come" ideas. The form is a participle.

might  -- "Might" is a particle used with verbs to indicate that the action is limited by circumstances or defined by conditions. There is no exact equivalent in English, but it is translated as "possibly," "would have", "might", "should," and "could."

 have -- (WT) This helping verb "have" indicates that the verb is the tense indicating an action completed in the past. This is not the tense of the verb here. 

 required  -- (WW) The word translated here as "required" is another rare word. This word means "passed over" and has more of a sense of "accomplish" or "achieve" something. However, it also can be "obtain". This word doesn't mean "required."  

mine own -- (WW) The word translated as "mine own" is the Greek word commonly translated as third-person pronouns in English.  This form would normally be translated as "it" since the form refers to the "money".  This word doesn't mean "mine own."  

with -- The word translated as "with" is also not from the word Christ uses to say "with." It is from a preposition that Christ rarely uses that means "along with" and, when referring to things "attached to" and "by means of." The last meaning makes sense here.

usury  -- The word translated as "usury" primarily means "childbirth" but specifically to the gestation period in the womb. You can see how the ide of bank interest arose from growth in the womb as a kind of slang. Money gives birth to more money. The word itself is a good summary of this verse.