When a word begins with an "s", do you use "a" or "an ...

u201 cs u201 d is a consonant, u201 can u201 d is only used prior to vowels. The reason for this is phonetic. We do not like the way u201 ca apple u201 d (for instance) sounds to the ear, so we include a consonant (in this case u201 cn u201 d) to make it sound smoother and more streaming.
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