Learn French: Le billet de train coûte dix-neuf euros.

In French, numbers 17, 18, and 19 are made by combining 10 and the single digit. So dix-neuf is literally 10 (dix) plus 9 (neuf). This hyphenated addition is the exact same pattern you use to build the larger numbers from 21 to 100!

How is dix-neuf euros pronounced?

There is a special sound connection (liaison) here. Usually, the f in neuf sounds like a normal 'f'. But when it is followed by specific words starting with a vowel, like euros, ans (years), or heures (hours), it softens into a 'v' sound. The two words flow together smoothly, sounding like 'dix-neuveuros'.

Why is it billet de train instead of billet du train?

When a noun is used to describe another noun's purpose or type, French simply connects them with de (of). You drop the article (le, la, etc.) before the second noun because you are talking about the general concept of a train ticket, rather than a ticket for one specific, physical train.

What is the dictionary form of the verb coûte?