For -- The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why". However, since this word always appears in the second position, it is more like an aside remark like, "as an explanation" or "as a cause".

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

say -- The word translated as "I say" is the most common word that means "to say" and "to speak", but it also means "to teach". The form Jesus uses to describe his own speaking can be either indicative, "I say/tell" or subjunctive, "I should/could say/tell". 

unto -- This word "to" comes from the indirect object form of the following word that requires the addition of a preposition in English. The most common is a "to" for the English indirect object. However, the translator can choose other prepositions: "with", "in", "of", "as", "by", "for", "at" or "on" depending on the context.

you, -- The Greek pronoun "you" here is plural and in the form of an indirect object, "to you", "for you", etc. 

that -- The word translated as "that" 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.  This word in exactly this form is repeated several times in this verse. This is very noticeable because it usually appears with a noun, but it doesn't anywhere here.

this -- "This" is a demonstrative pronoun that means "this", "here", "the nearer" and "the familiar".

that  -- The word translated as "the" 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", "those") than the English "the". See this article for more. 

is -- (WT, WF) This helping verb "is" indicates that the following verb is passive. Helping or auxiliary verbs are needed to translate the Greek verb forms into English. However, the tense here is the passive, past perfect, so "has been". This is not an active verb but a participle, a verbal adjective, ""having been." 

written -- "Is written" is the Greek verb that means "to mark", "to express by written characters", "to write a letter", "to write down" [a law], and so on. This is how Jesus always refers to the ancient writings of his people. The form is not just passive, but a past tense indicated something completed in the past, "has been written".

must -- (CW)  The Greek verb translated as "must" is a special verb that means "it/he/she needed," and "there was a need." It is not a helping verb like we have in English but an active verb. It is always singular, 3rd person, past tense. Its form is fixed and, when it refers to a verb, that verb's form is an infinitive like we say "he needed to go," but the subject is not separate from the verb.  

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

be -- This helping verb "be" indicates that the verb is passive. Helping or auxiliary verbs are needed to translate the Greek verb forms into English.

accomplished -- "Be accomplished" is translated from a Greek word, which means "to complete" and "to accomplish", especially in the sense of having a goal. It also means "to bring to perfection". The form is passive referring to a specific point in time. This is the verb form of the noun used as the end of this verse, which is translated as "end". This noun is discussed in this article on the "end" of the world.

in -- The word translated as "in" also means "within", "with" or "among". However, as an instrument or manner, it also means "by", which seems to the sense here.

me -- The "me" is in the indirect object form on the first-person pronoun, so usually "to me", though the form has other uses in Greek. 

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.

What follows is the paraphrase of a line of Isa 53:12 from the Septuagint.

And -- The Greek word translated as "and" is used as the conjunction "and", but it also is used to add emphasis ("also").

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

was -- This helping verb "was" indicates that the verb is passive. Helping or auxiliary verbs are needed to translate the Greek verb forms into English.

reckoned -- "He was reckoned" is from an uncommon verb for Jesus that means to "count", "reckon or calculate", "set down one's account", "take account", "consider", "conclude" or "infer". This is the verb form of the word usually translated in the NT as "word", but which doesn't mean that. Most about the noun form of this word in this article.

among  -- "Among" is the Greek word that usually means "with" or a related concept such as "among" or "by the means of". It also refers to "after" or "behind" when referring to a place, time or pursuit. In the version in Isaiah, this preposition is in the Greek usually translated as "in", which is used above.

the -- There is no Greek article "the" here in the source, but the noun is plural and in English, a definite article "the/this/that/these/those" is used before plural nouns in phrases like this.

transgressors-- "The transgressors" is another uncommon word for Jesus, also from the Greek Isaiah, that means "lawless", "impious" and "illegal". It too comes from Isaiah, but the form is different because the different preposition requires a different form. It does not appear with an article here, "the", but it does in Isaiah.

End of Isaiah quote.

for -- The word translated as "for" introduces a reason or explanation so "because" and, in questions, "why".   However, since this word always appears in the second position, it is more like an aside remark like, "as an explanation" or "as a cause".

 the -- The word translated as "the things" 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. However, this word is not in its plural form, "the things" but in the singular form that is used above to refer to "what is written".

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

concerning -- The Greek word translated as "concerning" means "around" when referring to a place, but, in this context, it means "about", "concerning", "on account of" and "in regard to". This is the way Christ usually uses it.

me -- "Me" is the regular first-person pronoun in Greek in the possessive form, so "my" or "of me".

have --The word translated as "have" means to "have", "possess", "bear", "keep close", "have means to do", "to have due to one" or "keep" and so on.

an  -- There is no indefinite article in Greek, but when a noun doesn't have a definite article, the indefinite article can be added in English translation.

end - (CW) The word translated as "end" means "purpose", "outcome", "something done" or "goal". It is the term Jesus uses to describe the culmination or the purpose of an era or lifetime. It is more of an accomplishment than simply ending a task. In some contexts, it refers to "having the power of deciding" and so "decision" and even "doom". It can mean what is "due" to the gods or the state.  See this article.