Os bilhetes para o concerto estão esgotados.

– bilhetes is the plural of bilhete, which is a masculine noun.
– Adjectives and past participles acting as adjectives must agree in gender and number with the noun they modify.
– Thus esgotados is masculine plural to match os bilhetes. If you were talking about as entradas (feminine plural), you’d say estão esgotadas.

– para expresses purpose or destination (“for the concert”).
– If you used do concerto (contraction of de + o), that would literally be “of the concert” or “belonging to the concert,” but it’s also quite common: os bilhetes do concerto estão esgotados is perfectly natural.
– Saying bilhetes de o concerto is ungrammatical; you must contract to do: bilhetes do concerto.

– esgotados comes from esgotar-se, meaning “to be exhausted, to run out.” In this context it means “sold out” (nothing left).
– vendidos means “sold” (they have been sold), but doesn’t necessarily imply that there are zero tickets remaining right now. Esgotados is the standard way to say “there are no more.”

Yes, there are a few informal alternatives:
• Já não há bilhetes para o concerto. (“There aren’t any tickets left for the concert.”)
• Os bilhetes já se esgotaram. (Using the pronominal verb esgotar-se: “The tickets have already sold out.”)

– In Brazil, ingressos is more common than bilhetes for concert tickets. You’d often hear os ingressos para o show estão esgotados.
– Otherwise, the structure (estão esgotados) is exactly the same.

Approximate IPA: /biˈʎe.tɨʃ/
• b as in English “bat”
• ilh as the palatal “lh” sound, similar to the “lli” in Italian “figlio”
• final es pronounced /ɨʃ/, a close central unrounded vowel + “sh” sound.