Jhn 8:49 I have not a devil; but I honour my Father, and ye do dishonour me.
I don't possess any second-rate spiritual power. However, I praise my father just as you insult me.
The word 'demon" doesn't necessarily mean "evil spirit" though that may well be the way the Jews used it. In Greek is used to refer to a controlling spiritual power, inferior to the gods. The thinking was that there were many types of spiritual powers active in the world, but for the Jew, only God held legitimate spiritual power. The Greek used this term to mean "knowing" and "skilled" in the sense that we might say, "He is a demon poker player."
Christ is often described by the Gospel writers as "casting out devils" but he only uses this word, daimonion a few times himself. More interestingly, he only uses it in the context of what others are saying about him. This idea of "evil spirits" is clearly not his, but he addresses it to deal with the way the people around him saw what was happening. More about this can be found in this long article about demons in the Gospels here.
The second sentence is set up as a contrast using the "alla..kai" (but...and) conjunctions in a way that is hard to capturing in English. Christ is accentuating his play on words, the positive "honor" with the negative "dishonor" with these conjunctions.
οὐκ "Not" is from οὐ ou which is the negative adverb for facts and statements, negating both single words and sentences. The other negative adverb, μή applies to will and thought; οὐ denies, μή rejects; οὐ is absolute, μή relative; οὐ objective, μή subjective.
ἔχω (1st sg pres ind act) "Have" is from echô (echo), which means "to have", "to hold", "to possess", "to keep", "to have charge of", "to maintain", "to hold fast", "to bear", "to keep close", "to keep safe," and "to have means to do."
"And" is from kai, which is the conjunction joining phrases and clauses, "and," or "but." After words implying sameness, "as" (the same opinion as you). Used in series, joins positive with negative "Not only...but also." Also used to give emphasis, "even", "also," and "just."
"You" is from hymeis, which are the singular nominative form of the second person, "you."
2nd pl imperf ind act) "Dishonor" is from atimazo, which means "to hold in no honor", "to esteem lightly", "to treat as unworthy," and "to bring dishonor upon."
"Me" is from eme, which means "I", "me", and "my".