Learn Italian: Mangio il cioccolato perché mi piace. - I eat chocolate because I like it.

In English, we say 'I eat chocolate' when talking about it in general. In Italian, you almost always need a definite article like il (the) before a noun when talking about it as a broad category or concept.

Where is the word for 'I' before mangio?

The word for 'I' is io, but Italian usually drops subject pronouns. The verb ending already tells you who is doing the action. The -o ending in mangio (from the verb mangiare) clearly means 'I eat'.

How exactly does mi piace translate to 'I like it' in this sentence?

The verb piacere works backward compared to English. Instead of saying 'I like it', Italians literally say 'it is pleasing to me'. The word mi means 'to me', and piace means 'it is pleasing'. Here, the 'it' refers back to the chocolate.

Does perché mean 'because' or 'why'?

It means both! perché is a very handy word because you can use it to ask 'why?' in a question, and also to say 'because' in your answer. Notice the accent mark on the é, which reminds you to stress the final syllable when speaking out loud.