Learn French: Août est un mois de vacances.

It looks intimidating, but it is actually very short! It is usually pronounced just like the 'oo' in 'boot' (or like the French word ou). Some French speakers also pronounce the 't' at the end, making it sound like 'oot'. Both ways are perfectly fine.

I learned that months are not capitalized in French. Why is Août capitalized here?

You are right! Normally, months are written with a lowercase letter in French. However, because Août is the very first word of the sentence, it gets a capital letter just like any other word would.

The word mois ends in an 's'. Does that mean it is plural?

Not in this case! Mois is one of those French words that naturally ends in an 's' even in its singular form. You can tell it is singular here because of the word un (a) right before it. To say 'two months', you would say deux mois—the spelling does not change.

Why does French use de vacances instead of just saying un vacances mois?

In French, you cannot stack nouns next to each other to make a description like we do in English with 'holiday month'. Instead, you have to link them using de (of). So, you are literally saying 'a month of holidays'.

Why is vacances plural here when the English translation says 'a holiday'?