missing "the/this"  -- (MW) The untranslated word is the Greek definite article," the," 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," and "those"). See this article for more. 

My -- (CW) "My" is the first-person adjective, not the common pronoun, used in Greek to create a possessive or as the object of a preposition. Unlike the genitive pronoun used as a possessive, its case matches its noun. Perhaps "mine own" captures its best.

missing "the/this"  -- (MW) The untranslated word is the Greek definite article," the," 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," and "those"). See this article for more. 

command  -- The word translated as "command" has the sense of a direct "order" or "command" given by someone as opposed to a body of law or tradition in society. Jesus uses it to refer to the written Law, his lessons, and the commands given by someone in authority.

is -- The verb "is" here is the common form of "to be" in Greek. It means to have a certain characteristic or remain in a certain condition. It also equates terms or assigns characteristics.

this -- "This" is translated from a Greek adjective that means "this," "that," "the nearer." Without a noun, it has the sense of "this one" or "that one." It is in the form of a subject.

missing "that"  -- The word here is usually translated as "that" or "because" but it is also used to introduce commands when it is not translated. The following verb could be translated as a command or a statement. Here, it is a command.

Love -- (CW) The word translated as "love" expresses a lot of different ideas including "to be fond of," "to greet with affection," "to persuade," and "to be contented with." Jesus however, applies it to relationships where we have a duty to care for others: family, God, etc. Another word, also translated as "love," is used to for relationships of affectionate friendship that are more voluntary. To distinguish this word, translating it as "cares for" seems to work best. See this article on love for more information.

each other --  "Each other" is a special adjective that means literally "one another."

as -- "As" is from a Greek word that means which means "even as," "how," and, in relating to time, "as" and "when."

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

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.

loved -- (CW) The word translated as "love" expresses a lot of different ideas including "to be fond of," "to greet with affection," "to persuade," and "to be contented with." Jesus however, applies it to relationships where we have a duty to care for others: family, God, etc. Another word, also translated as "love," is used to for relationships of affectionate friendship that are more voluntary. To distinguish this word, translating it as "cares for" seems to work best. See this article on love for more information.

you. -- The "you" here is the second-person, plural pronoun in the form of an object of the action or preposition. As the object of a preposition, an accusative object indicates movement towards something or a position reached as a result of that movement.