Question

the letters staring vowel sound but it is a consonant​

Answer 1

Honest” starts with a consonant (“h”) but sounds like it begins with a vowel (“o”). This is referred to as the “h” being “silent”.

There are no words beginning with consonant sounds that use “an" as an indefinite article. It occurs only before vowel sounds. ... So words like “unit,” “ Europe,“ “university,” “uterus,“ etc. all take “a" because they begin with the consonant sound /y/.