Learn Icelandic: Fuglarnir syngja mikið í dag. - The birds are singing a lot today.

The basic word is the masculine noun fugl. First, we make it plural by adding -ar to get fuglar (birds). Then, because we want to say 'the' birds, we add the plural definite ending -nir, giving us fuglarnir.

Why is there no word for 'are' when the English translation says 'are singing'?

Icelandic doesn't use a separate continuous structure like English 'are doing'. The single verb syngja means both 'sing' and 'are singing', and you can tell which one it is from the context of the sentence.

Why is the word mikið used here instead of a word for 'many'?

Mikið means 'a lot' or 'much'. Here it is acting as an adverb describing the action of singing (how much the birds are singing). If you wanted to say there were 'many' birds, you would use a plural adjective like margir instead.

Does í dag literally translate to 'today'?

It literally translates to 'in day', but this two-word phrase is the standard everyday Icelandic way to say 'today'.