fils

The French word fils, as you probably know if you've had more than a couple of French lessons, means son.

But the interesting thing is that the final -s is pronounced. Although in the majority of cases, the final -s isn't pronounced on words in French, fils is one of a smallish number of cases (and one of a very small handful of common cases) where the final -s is pronounced.

Some what other words have the final -s pronounced in French? Well, firstly a couple of common cases:

- cassis ("blackcurrant")
- os ("bone"), at least in the singular;
- plus, when it means more.

Then, other good candidates are words that end in an -s in the singular, and which don't "look like normal French words". Common examples are:

- Words ending in the Latin(ate) suffix -us (and occasionally -is). Thus, speakers generally always pronounce the final -s of processus ("process") and sinus ("sine", "sinus") and most pronounce the final -s of détritus ("litter", "trash"). The final -s of cannabis is also pronounced.
- Slang words practically always have the final -s pronounced: "cassos!" let's split!, rapidos on the double, gus bloke.

The ending -is is a little difficult. In many words ending in -is, the final -is isn't pronounced where the word is felt to be a "normal" French word: for example, it isn't pronounced in coulis, frottis, paradis...