How do you say “b” in Vietnamese?

“B” in Vietnamese is si (si).

Vietnamese words for “b”

• siListennoun
  Hanoi [si˧˧] · Saigon [ʂɪj˧˧]si level

  si; B

Translations matched from English Wiktionary (translation tables and Vietnamese entries, via kaikki.org; CC BY-SA 4.0) and the NgonNgu English–Vietnamese dictionary, reviewed and edited; examples from Tatoeba (CC BY 2.0 FR). The Listen button uses your browser's Vietnamese voice.