Use Of The A And An Questions Medium
Yes, you can use "a" or "an" before words starting with a silent "j." The choice between "a" and "an" depends on the sound that follows the article, not the silent letter at the beginning of the word.
For example, you would say "a jalapeno" because the sound that follows the article is a consonant sound (/dʒ/), even though the "j" is silent. Similarly, you would say "an hour" because the sound that follows the article is a vowel sound (/aʊ/), even though the "h" is silent.