Learn Croatian: Idem ravno, a ti ideš lijevo. - I go straight on, and you go left.

In Croatian, you usually drop subject pronouns like ja (I) or ti (you) because the verb ending already tells us who is doing the action. However, here ti is included to create a strong contrast between what I am doing and what you are doing.

Why is the word a used for 'and' here instead of i?

The word a is a conjunction used when you are contrasting two different things, often translating to 'and', 'but', or 'while' in English. Since my direction (ravno) is being contrasted with your direction (lijevo), you must use a. If you were just adding similar non-contrasting information, you would use i.

Do the words ravno (straight) and lijevo (left) change depending on who is going?

No, ravno and lijevo act as adverbs of direction here. Unlike adjectives, adverbs never change their endings to match the gender or number of the person moving. They will always keep these exact spellings.

How do we know idem means 'I go' and ideš means 'you go'?