French is known to be a very musical language because words flow from one to the next with no hiatus (a pause that happens when there are adjacent vowel sounds). This is called euphony (agreeable or harmonious sounds). In French, when euphony can't happen naturally, you add different sounds or words to avoid it.

Here are the various ways to maintain euphony in French:

- Some adjectives have euphonic forms, i.e. their spelling changes in front of a masculine noun that begins with a vowel or a mute h.

For example:

Un bel avion = A beautiful plane

Un fol espoir = A wild hope

Un nouvel homme = A new man 


- In inverted questions in French, we add a "t" in to avoid two vowel sounds clashing.

For example:

A-t-il sorti les poubelles ? = Did he take the bins [US: the trask] outside?

Aura-t-elle son diplôme ? = Will she get her degree?

Mange-t-on bien dans ce restaurant ? = Do you eat well in this restaurant?


- In L'Impératif, we add an "s" to the 3rd person form when it is followed by the adverbial pronouns "y" or "en".

For example:

Va au cinéma ! Vas-y ! Go to the cinema! Go there!

Mange de la soupe ! Manges-en ! = Eat some soup! Eat some of it!


- The case of "l'on": you add the definite article l' in front of the subject pronoun "on" after "que, lorsque and puisque", to avoid a hiatus or to avoid the repetition of the sound 'con' (swear word in French).

For example:

Je veux que l'on parte maintenant ! = I want to leave now!

Si l'on avait su, on serait partis plus tôt. = If we'd known, we'd left earlier.

Il faut que l'on complète ce formulaire. = We must fill in this form.


Let me take a look at that...