Questions & Answers about Já, maðurinn er veikur.
Since this lesson is about yes/no questions, how would I turn this statement into the question 'Is the man sick?'
To make a yes/no question in Icelandic, you swap the subject (maðurinn) and the verb (er). So the question becomes Er maðurinn veikur? This puts the verb in the first position, which is why it is called V1 word order.
Could I use jú instead of já to say yes here?
No, you only use jú when you are answering yes to a negative question (for example, if someone asked 'Is the man not sick?'). Since the question we are answering here was positive, you must use the standard word for yes, which is já.
The dictionary says the word for man is maður, so why is it maðurinn here?
In Icelandic, the word for 'the' is usually added to the end of the noun instead of being a separate word. Maður means 'a man', and adding the masculine attached article -inn makes it maðurinn, meaning 'the man'.
Why does the word for sick end in -ur (veikur)?
Adjectives in Icelandic change their endings to match the gender of the noun they describe. Because maðurinn is a masculine noun, the adjective takes the standard masculine singular ending -ur. If we were talking about a woman, the feminine form would just be veik.