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

are -- This helping verb indicates the present tense of the verb. It is used here to form the present, progressive tense, which doesn't exist in Greek but which can smooth the flow of English sentences.

you , -- This comes from the plural, second-person form of the verb above.

talking -- (CW) "Talking " is a verb that means "to calculate exactly", "to add up account", "to debate," and "to argue." It is not a common word. Jesus only uses it seven time, but he often uses it, as he does here, with the word "heart."

about -- The word translated as "about " introduces a statement of fact or cause so  "with regard to," "that" or "because."

you -- This comes from the plural, second-person form of the verb below.

having --  (WF) The word translated as "having" means to "have", "possess", "bear", "keep close", "have means to do",  "to have due to one", or "keep" and many specific uses. This verb isn't used to form past tenses as it is in English. 

no -- (WP) The Greek word translated as "no" 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.

bread? -- (CW, WN) The word translated as "bread" means "small loaf or cake of bread". It is more like a slice of bread today.

Do -- This English helping verb is used to create questions, commands, negative statements, and smooth word flow in translation from Greek

you -- This comes from the plural, second-person form of the verb below.

still -- "Still " is an adverb that means "not yet" and a strong form of "not" and "not at all." It begins the clause about perceiving.

not -- This is from the word above that is negative.

see -- (CW) "See"  from a verb that means "to perceive with the eyes," "to perceive with the mind," and "to observe." We use the word "see" to have the same sense of physical seeing and perceiving with the mind. This is the root word for the key word in Jesus's teaching that gets translated as "repent" but which actually means "change your mind."  There are several words translated as "understand" in the Gospels, but this word might be closest. This is not one of the common words translated as "see."

or --  (CW) "Or" is from a Greek negative meaning "but not" and as both parts of "neither...nor." This is not the common word translated as "or."

understand? -- The word translated as "understand" means "to bring together." It means "understand" in the same sense that we say "put it together" to mean "understand." This word is always translated as "understand" in the KJV translation. A number of other Greek words begin with the same prefix, and all mean some form for bringing things together, for calling a meeting to gathering a crop.

Are -- (WW) The word translated as "have" means to "have", "possess", "bear", "keep close", "have means to do",  "to have due to one", or "keep" and many specific uses. This verb isn't used to form past tenses as it is in English, which is confusing in this context. Specifically, it is not used here to form the past perfect tense of "hardened" but is needed in English to do so. It can also mean "possess mentally" and "keep still" both are relevant here where its sense is "hold" in the was we use "are stuck mentally."

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.

your -- The word translated as "your" is plural addressing a group of Jesus's listeners. This comes after the word "heart."

hearts -- (WN)  "Heart" is the Greek word that means "heart" both the physical organ and as the seat of emotions, which we discuss in a larger Greek context in this article here. However, this phrase can be read as defining the "heart" and both the "soul" and "the mind". This word is not plural but singular. WN  --Wrong Number- The word "hearts" is translated as plural but the Greek word is singular.

hardened? -- (WF, WT)  "Harden" is a verb that means "to petrify", "to turn into stone," and "to harden." It is in the form of an adjective in the same singular form as "heart." The tense is the past perfect, so the sense is "having hardened." The "have" above is not part of this verb but it is a past perfect tense. This verb comes first in the clause, introducing the rest.