Learn French: Sont-ils enthousiastes ? Ils le sont toujours. - Are they enthusiastic? They always are.

When a pronoun replaces an adjective or a state of being rather than a specific noun, French uses the invariable neuter pronoun le. It never changes to la or les, regardless of the gender or number of the subject it refers back to.

Why do we even need le here? In English, we just say 'They always are.'

In French, you generally cannot leave the verb être (to be) hanging without its complement when referring back to a previously mentioned state. You must use the neuter le to stand in for the missing adjective. It functions similarly to saying 'They always are so' in older or formal English.

Could we say Ils toujours le sont to match the English word order?

No, because adverbs like toujours must generally follow the conjugated verb in French. Even though English puts the adverb before the verb ('always are'), French places it immediately after the conjugated verb sont, resulting in Ils le sont toujours.

Is there a liaison between sont and ils in the first sentence?

Yes! Because this is a formal inverted question, the liaison is mandatory. The 't' in sont connects to the vowel in ils, making it sound like 'son-teel'.