Who, -- (OS) There is nothing in the Greek that can be translated as "who" in the source we use today but it does exist in the source that the KJV translators used.

when -- (WW) The word "when" means "but," "however," and "on the other hand." It joins phrases in an adversarial way. Since it always falls in the second position, translating it as "however" often captures its feeling better.  

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

had -- (WT) This helping verb "had" indicates that the verb is the tense indicating an action completed in the past. The tense is the normal tense of a story, that of something happening as a specific time past, present or future.

found  - (WF) The term used for " found" is from the source of our word, "heuristic," meaning enabling a person to find out something for themselves. It means "find out" and "discover." It is a participle, "finding." The tense is the normal tense of a story, that of something happening as a specific time past, present or future.

one  - -- The Greek word translated as "one " means "one" (as opposed to other numbers), "single," and "one and the same."As in English, it can be used as a pronoun, meaning a single person.

pearl  - The word for "pearl" is a metaphor in Greek for "wisdom" as we would say in English "pearls of wisdom."

of great price,  - (WF) The adjective translated as "of great price" primarily means "much revered" from a word translated mostly as "honored" in the Gospels. "Jesus only uses this word here. As you can see, that idea creates a double meaning "valuable pearls" and "revered wisdom." The root word means "honor" and "esteem." The prefix means "many" or "much."  It sense of "price" is tangential to the idea of "value."

went -- (WF) The Greek verb translated as  "went" means "to go away," "to depart from," "to spread abroad," and "to depart from life."  It is a participle, "departing." The tense is the normal tense of a story, that of something happening as a specific time past, present or future

and -- (IW) There is nothing that can be translated as "and" in the Greek source. It was added because the following verb is translated as active  rather than a participle.

sold  - (WF) Interestingly, the verb for "sold" here is different than the "sell" in Matthew 13:44 . Here, the word means "to sell" or "to export," but it is specifically used to mean selling into slavery and selling for a political bribe, and is a metaphor for being betrayed or ruined. In English, the idea of "selling out" comes close to this idea. The form here is an infinitive, connecting to the "departing to sell out,"

all  - The word translated as "all" is one word meaning "all," "the whole," "every," and similar ideas. As an adverb, it means "in every way," "on every side," and "altogether."

that  - (WW) The word translated as "that" means "as great as,"" "as much as," and similar ideas of comparison.

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

had,  - The word translated as "had" means "to possess" or "to keep."

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

bought -- "Bought" is a verb that Jesus only uses eight times that means "to occupy a marketplace," "to buy in the market," and "to buy for oneself." Jesus always seems to use it in the sense of "buy for oneself."

it. -  - -- The word translated as "it" is the Greek word commonly translated as third-person pronouns in English.