Questions & Answers about Lounas on tänään hyvä.
Why is the word for good here hyvä and not the partitive hyvää? I thought food takes the partitive.
Even though it relates to food, lounas (lunch) is considered a countable noun in Finnish, much like an event. Mass nouns like kahvi (coffee) or ruoka (food) take the partitive ending in sentences like this (for example, ruoka on hyvää), but countable nouns just take the basic dictionary form hyvä.
Could I put tänään at the beginning or end of the sentence?
Yes, Finnish word order is very flexible. Tänään lounas on hyvä or Lounas on hyvä tänään are both perfectly fine and mean the same thing. Putting tänään right after the verb is just a very natural, common way to structure it.
There is no word for "the" here. How do we know it means a specific lunch?
Finnish does not have articles like "a" or "the". You have to tell from the context! Here, because it says tänään (today), we know it is talking about a specific lunch happening today, so we naturally translate it as "the lunch" or just "lunch today" in English.