Learn Hardcore French: Le chocolat fond vite sous ce climat chaud. - The chocolate melts quickly in this hot climate.

The infinitive is fondre (to melt). In the present tense, the 3rd person singular form is fond (je fonds, tu fonds, il/elle/on fond). There’s no t at the end—just the silent d—so it’s spelled fond and pronounced /fɔ̃/.

Why do we say Le chocolat with the article le? Couldn’t it be du chocolat?

In French, when you talk about something in general (the whole category), you use the definite article (le, la, les).
• Le chocolat = chocolate in general.
A partitive article (du) indicates an unspecified quantity of something:
• du chocolat = some chocolate (a portion, not the concept itself).

Why is vite placed immediately after fond?

Short adverbs of manner (like vite, bien, mal) typically follow the conjugated verb in French:
• fond vite.
Longer adverbs (e.g. rapidement) also go right after the verb, but they sound more formal.

Why do we use sous ce climat chaud instead of dans ce climat chaud?

French prefers the idiomatic expression sous un climat (“under a climate”) to convey being exposed to certain weather conditions. You could say dans ce climat, but sous ce climat chaud is more natural to stress that the heat is “bearing down” on the chocolate.

Why is the adjective chaud not chaude?

The noun climat is masculine (le climat), so the adjective must agree in gender and number. Masculine singular adjectives take the form chaud (no e).

Can I say Le chocolat fond rapidement instead of Le chocolat fond vite? Is there a nuance?

Yes, both mean “melts quickly.”
• vite is shorter and more colloquial.
• rapidement is longer and more formal.
Neither changes the core meaning; it’s just a question of register.