Do not treat three spellings as one fixed rule
The spellings ai and ais often point toward /ɛ/, while the conjunction et is commonly /e/ in reference French. But word, grammatical form and variety matter. Check a model for the exact form instead of pronouncing every ai as the English word “eye.”
Compare lait, mais and et as familiar examples. Keep each vowel steady. Then look at the word in a sentence so you know which grammatical form you are reading. Endings such as -ai and -ais can be treated differently by speakers; a written distinction is not a guarantee that every variety maintains the same spoken contrast.
The é, è and e guide provides the underlying vowel comparison. Use the vowel trainer to hear /e/ and /ɛ/, then try the two complete sentences below.
Compare the two vowel targets
Keep both vowels steady. For /e/ your jaw is a little closer; for /ɛ/ it opens a little more. Use the vowel trainer above to compare the two reference sounds, then listen for them inside the complete lines.
Hear the spellings in two complete sentences
Listen first, answer the question, then open the transcript. Both models are complete synthesized lines from Parle’s course, from two separate scenes.
Listen to a film reaction
Which word introduces the drawback: et or mais?
Check the film answer and transcript
Oui, c’était intéressant, mais un peu long.
Yes, it was interesting, but a bit long. Était means “was”; mais introduces the drawback. Listen again and repeat the whole reaction.
Listen to a weekend story
After having coffee, did the speaker go to the market or the cinema?
Check the weekend answer and transcript
J’ai pris un café et je suis allé au marché.
I had coffee and went to the market. The ai in j’ai commonly sounds like /e/. The conjunction et joins the two actions; its final t is silent.
Put the spellings into a new sentence
Complete the written line with ai, et, mais and ait. Read your completed version aloud.
J’___ pris un café ___ un croissant, ___ le café ét___ froid.
Check the written answer
J’ai pris un café et un croissant, mais le café était froid.
I had a coffee and a croissant, but the coffee was cold. Et adds the croissant, mais adds the contrast, and était describes the coffee.
For the pronunciation references, see the OQLF’s examples of -ai and the Académie française’s entry for et.