"You like chocolate."
Translation:Is maith leat seacláid.
Neither liom or leat mean "like".
liom and leat are "prepositional pronouns", a combination of the preposition le and a pronoun. The pronoun says who is doing the liking (or hating or what every other judgement is being expressed in this type of statement).
Is maith liom úlla - "I like apples"
Ní maith leat úlla - "You don't like apples"
Is fuath leis úlla - "He hates apples"
An maith léi úlla? - "Does she like apples?"
Is breá linn úlla - "We really like apples"
Is aoibhinn libh úlla - "Y'all love apples"
Is cuma leo - "They don't care"