Use Of The A And An Questions Medium
You should use "an" before words starting with a silent "b." The use of "an" is determined by the sound of the following word, not the actual letter it starts with. Since the silent "b" does not produce a sound, the word following it would typically begin with a vowel sound. Therefore, "an" is used to maintain the smooth flow of speech. For example, you would say "an hour" (pronounced as "an ow-er") and "an honest person" (pronounced as "an on-est person").